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Motorcycle Suspention & Spring Resources

product manuals

We sell tens of thousands of different parts, and some are more complex than others. Our motorcycle sSuspention & spring resources page is where you come to find out technical data, model fitments and sales details about some of our more complex kits and assemblies

Teknik Fork Spring Installation Guide

After purchasing a set of Fork Springs from Teknik Motorsport, read this quick installation guide.

Click to download the Teknik Fork Spring Installation guide or scroll down to the bottom.


We know suspension. That’s what we do!

Teknik Motorsport would like to thank you for purchasing a part of our huge range of suspension springs. All of our springs are made of a higher quality wire, this allows us to produce a lighter, more stable product. The purchase of higher quality wire has allowed us to fine tune the stress relief process and remove most of the residual stresses that occur in wire when wound into a spring. Therefore, we are now able to manufacture a product that will sag less, travel more and is less likely to break. The Signature Series springs are further processed and finished for an even higher quality spring than the normal stock.


HOW TO INSTALL YOUR TEKNIK FORK SPRING

Recommended Preload

Standard preload for full size dirt bikes – 3 to 10 mm

Standard preload for road bikes – 0mm for sport bikes, up to 25mm for cruisers. Top out spring fully compressed

Standard preload for 80cc mini dirt bikes – 5 mm

Notes on preload: The amount of preload required depends on the sprung weight of bike and rider, the rate of the spring, the front to rear weight bias, the fork angle and personal preference. There is no magic preload number. If you like the feel of the bike with less or more preload than these guidelines, great. More preload means the front and sits higher. This will make the bike turn slower. Less preload means the front end sits lower. This will make it turn quicker and it will feel softer and bottom easier (though spring rate has a bigger effect on bottoming than preload does). Higher oil level does not affect static sag but does increase bottoming resistance.

Determining the preload spacer length

External top-out

Assemble the forks without the springs and spacers. Install the emulator (if used). Extend the fork all the way. Drop the spring and spring washer into the fork tube. Use a tape measure to record the distance from the top of the fork tube down to the top of the spring washer. Measure the fork cap height from the bottom of the sealing lip (the point that touches the top of the tube when the cap is tightened) to the point on the bottom of the cap where the spring touches (this point might be on a special spacer or washer). Subtract this distance form the first measurement (down to the top of the spring washer). This would be the required length of the spacer for zero preload. Add the amount of preload required to determine the length of your spacers. Be sure to put spring washers on both ends of the preload spacer during final assembly and include them in your calculations.

Internal top-out

This type requires you to measure the set length of the fork.

Measuring the set length is best accomplished with the cartridge out of the fork; however, it can be done with the fork spring out and the cap unscrewed form the outer tube but still attached to the damping rod. Collapse the fork tube. The set length is measured from the point the spring touches on the top of the cartridge to the point the spring touches on the cap with the rod fully extended. (Sometimes the point the spring touches on the cap is actually a special washer or spacer.) A tape measure can be put down the fork tube with the spring removed, if you are careful to make sure the tape is resting on the flange when measuring.

Once the set length is recorded, measure the length of the spring and subtract. This would be the required length of the spacer for zero preload. Add the amount of the preload required to determine the length of you spacers. Be sure to include spring washer thickness as they are required on both ends of the preload spacer.

Teknik Motorsport warranty for motorcycle springs

Our products are manufactured or sourced from the very best materials and suppliers worldwide.

That's why we can proudly offer a lifetime warranty on our springs.

You buy in total confidence that the products you buy have been quality researched, developed and manufactured to our exacting specifications, so you can get the most out of your suspension.

1- Teknik lifetime warranty

Teknik warrants to the original retail purchaser who retains ownership of the motorcycle on which the spring was originally installed, the springs are covered against factory defects in material and workmanship (not on the finish) when used correctly.

2- What will be done?

Upon verification of warrant coverage, Teknik will either replace defective or prematurely worn out products without charge. This is the purchases sole and exclusive remedy for any loss or damage however arising due to a non-conformity or defect in the spring.

3- Warranty Claim Procedure

To make a claim under this warranty, the purchaser should contact the dealer in which the spring was purchased from. Teknik reserves the right to test the returned spring so as we can evaluate the non-conformity or possible defect. The purchaser is responsible to pay all the cost of removal and installing of the spring to the motorcycle and to ship the product back to the dealer where purchased, then to Teknik Motorsport then back to the dealer, then back to you. Teknik will not accept any springs sent directly to them.

4- Warranty Exclusions

This warranty does not cover any springs that have been improperly installed. The springs should be installed by a qualified suspension specialist whom is experienced in the removal and fitting of the springs. Other things this warranty does not cover are springs which have been improperly serviced, springs that have been misused, any spring that has been modified or altered or that are subject to negligence, accident or collision, improperly installed or wrongly installed on a vehicle in which it wasn’t designed for, or any vehicle in which carries more than the manufacturers suggested weight. Teknik holds the right to make any changes in materials, specifications and design to make changes they feel necessary without giving prior notice or assuming any obligations to modify any spring previously manufactured.

5- More Exclusions

This warranty states that Teknik will warrant the entire spring that may not be modified or supplemented by any other company or person either in writing or verbal statements. Any descriptions made above about the product in conjunction with this warranty is only for identification purposes. This does not mean the product described above will be the product you receive. Any spring used to demonstrate what this warranty covers is not necessarily the product you will receive. Any statements (meaning written or verbal) made by any salesman will not over ride this warranty. The description on this page is final there are no other warranties in which will exceed this one. Any other warranties that may be implied are denied to the upmost extent allowed by the law. In no way will the refund exceed the purchase price. Some states do not allow constraints on how long an implied warranty will last.

This warranty will in noway cover any accidental damages, loss of time, any disadvantage that the purchaser may experience, loss of use of the motorcycle or any damage done to the motorcycle. This warranty will not cover any unintentional or unintended damages. Some states do not allow constraints of incidental or substantial damages, so the above information does not apply to you.

This warranty will give the purchaser certain legal claims, the purchaser may also have other claims which may change from place to place.

Note: Teknik Motorsport makes no warranties either expressed or implied. We shall not be liable for any loss, damage, injury, or death arising from the use of our product. User assumes all responsibility and risk. Motorcycle riding/racing can be a DANGEROUS activity. Teknik Motorsport owners & employees make no claims as to accuracy of suggested applications of items. ITEMS ARE ONLY SUGGESTIONS.

 

Teknik Shock Spring Installation Guide

After purchasing a Shock Spring from Teknik Motorsport, read this quick installation guide.

Click to download the Teknik Shock Spring Installation guide or scroll down to the bottom.


We know suspension. That’s what we do!

Teknik Motorsport would like to thank you for purchasing a part of our huge range of suspension springs.


HOW TO INSTALL YOUR TEKNIK SHOCK SPRINGS

1. Remove the existing spring

Using your motorcycle owner’s manual remove the existing spring.

2. Install the spring

Once the spring is removed be sure to not lose any of the unattached parts, install the spring. Once the suspension component is put back together re-fit your suspension to the bike.

3. Setting up the static sag and rider sag

* Rider sag is the amount a bike sags with the rider in a seated position.

* Static sag is the amount that a bike sags under its own weight.

First, measure and set rider sag, and then measure static sag.

Rider sag is set at a predetermined amount, to allow the suspension to operate in the correct part of its stroke. Typically, rider sag is about one-third of suspension travel. Motocross bikes and offshoots of them like the WR400/426 typically use 100mm of rider sag. Bikes like XRs, TTRs and other trail bikes use 85mm, and bikes in between, such as DRZ, use 90-95mm. The KTM PDS system works best with 90mm. Road bikes do vary model to model, but 35-40mm is often used for sports bikes. Sag is adjusted by increasing or decreasing spring preload by turning the threaded preload collars on top of the shock spring. Increasing spring preload will give you more ride height/less sag, and vice versa. Rider sag and static sag are determined by making measurements of the bike when loaded and unloaded. It is vital that the measurement is made from the same two points in each stage of the process.

4. Rider sag test

  • Put the bike on a stand with the rear wheel off the ground. With a texta, make two marks, one on the rear fender, directly above the axle, and the other on the top of the axle nut. Measure the distance between the two marks. Our example is 650mm.
  • Take the bike off the stand, and have the rider to sit on the bike in their normal riding position, with all their weight on the bike. Take another measurement between the same two points. Our example is 550mm
  • The rider sag in our example is 100mm. If you're making this measurement on an MX bike you're spot-on.

5. Static sag test

  • Allow the bike to rest on the ground, without a rider. You will need to help it balance. Take another measurement from your two-texta marks. Push the seat down and then let it up by itself. Take a measurement. Pull the seat up and then let it go. Take another measurement. If there are any variations, use an average. If there is more than 5-7mm difference, you may have a problem with binding in the linkages. Our example is 610mm.
  • Subtract this measurement from your first one (650mm, remember?). Static sag should be between 18mm and 32mm for dirt bikes and 5-15mm for road. (please see www.teknikracing.com for the road bike suspension tips in more detail) If it's less then 18mm, the shock spring is too soft for you. If it's more then 32mm, the spring is too hard. 25mm to 30mm is ideal. In our example, static sag is 40mm, so a softer spring needs to be fitted.

After all this, you might be wondering how important sag height is. A spring is just a spring right? Wrong!

  • Soft springs need too much preload to prevent the bike riding low in the shock’s stroke, causing harshness, and making it kick on the entry to corners, especially in braking bumps.
  • Hard springs won’t allow proper squat, making the rear-end uncompliant. Your bike will ride high in the rear, increasing headshake.

Many MX bikes are made with a higher steering head angle, which causes them to steer slower in the bush. For MX models, reduce static sag by 5mm to tighten the steering angle.

Teknik Motorsport warranty for motorcycle springs

At Teknik we know suspension, that's what we do!

Our products are manufactured or sourced from the very best materials and suppliers worldwide. That's why we can proudly offer a lifetime warranty on our springs.

You buy in total confidence that the products you buy have been quality researched, developed and manufactured to our exacting specifications, so you can get the most out of your suspension.

1. Teknik’s lifetime warranty.

Teknik warrants to the original retail purchaser who retains ownership of the motorcycle on which the spring was originally installed, the springs are covered against factory defects in material and workmanship (not on the finish) when used correctly.

2. What will be done?

Upon verification of warrant coverage, Teknik will either replace defective or prematurely worn out products without charge. This is the purchases sole and exclusive remedy for any loss or damage however arising due to a non-conformity or defect in the spring.

3. Warranty Claim Procedure.

To make a claim under this warranty, the purchaser should contact the dealer in which the spring was purchased from. Teknik reserves the right to test the returned spring so as we can evaluate the non-conformity or possible defect. The purchaser is responsible to pay all the cost of removal and installing of the spring to the motorcycle and to ship the product back to the dealer where purchased, then to Teknik Motorsport then back to the dealer, then back to you. Teknik will not accept any springs sent directly to them.

4. Warranty Exclusions.

This warranty does not cover any springs that have been improperly installed. The springs should be installed by a qualified suspension specialist whom is experienced in the removal and fitting of the springs. Other things this warranty does not cover are springs which have been improperly serviced, springs that have been misused, any spring that has been modified or altered or that are subject to negligence, accident or collision, improperly installed or wrongly installed on a vehicle in which it wasn’t designed for, or any vehicle in which carries more than the manufacturers suggested weight. Teknik holds the right to make any changes in materials, specifications and design to make changes they feel necessary without giving prior notice or assuming any obligations to modify any spring previously manufactured.

5. More Exclusions.

This warranty states that Teknik will warrant the entire spring that may not be modified or supplemented by any other company or person either in writing or verbal statements. Any descriptions made above about the product in conjunction with this warranty is only for identification purposes. This does not mean the product described above will be the product you receive. Any spring used to demonstrate what this warranty covers is not necessarily the product you will receive. Any statements (meaning written or verbal) made by any salesman will not over ride this warranty. The description on this page is final there are no other warranties in which will exceed this one. Any other warranties that may be implied are denied to the upmost extent allowed by the law. In no way will the refund exceed the purchase price. Some states do not allow constraints on how long an implied warranty will last.

This warranty will in no way cover any accidental damages, loss of time, any disadvantage that the purchaser may experience, loss of use of the motorcycle or any damage done to the motorcycle. This warranty will not cover any unintentional or unintended damages. Some states do not allow constraints of incidental or substantial damages, so the above information does not apply to you.

This warranty will give the purchaser certain legal claims, the purchaser may also have other claims which may change from place to place.

Note: Teknik Motorsport makes no warranties either expressed or implied. We shall not be liable for any loss, damage, injury, or death arising from the use of our product. User assumes all responsibility and risk. Motorcycle riding/racing is a DANGEROUS activity that can lead to permanent disability or death. Teknik Motorsport owners & employees make no claims as to accuracy of suggested applications of items. ITEMS ARE ONLY SUGGESTIONS.

2017 KTM PDS Rear Shock Spring Rates

If you have a 2017 KTM, you have a huge range of options with Teknik. We offer over twice as many progressive rate springs as WP.

Click to download original or scroll down to the bottom.


2017 KTM PDS Spring Recommendations

 

In Gear

250/300EXC

250EXCF

350EXCF

450EXCF

500EXCF

 

55-65kg

54-57-60

54-57-60

54-57-60

57-60-63

57-60-63

 

65-75kg

57-60-63

57-60-63

57-60-63

60-63-66

62-63-66

 

75-85kg

60-63-66

60-63-66

60-63-66

63-66-69

63-66-69

STD Progressives

85-95kg

63-66-69

63-66-69

63-66-69

66-69-72

66-69-72

 

95-105kg

66-69-72

66-69-72

66-69-72

69-72-75

69-72-75

 

105-115kg

69-72-75

69-72-75

69-72-75

72-75-78

72-75-78

 

115-125kg

72-75-78

72-75-78

72-75-78

75-78-81

75-78-81

 

125-135kg

75-78-81

75-78-81

75-78-81

78-81-84

78-81-84

 

Spring list           Progressive

20-070--54-60      PDS Progressive Shock Spring 59/61/230mm 54-57-60N ORANGE

20-070--57-63      PDS Progressive Shock Spring 59/61/230mm 57-60-63N ORANGE

20-070--60-66      PDS Progressive Shock Spring 59/61/230mm 60-63-66N ORANGE

20-070--63-69      PDS Progressive Shock Spring 59/61/230mm 63-66-69N ORANGE

20-070--66-72      PDS Progressive Shock Spring 59/61/230mm 66-69-72N ORANGE

20-070--69-75      PDS Progressive Shock Spring 59/61/230mm 69-72-75N ORANGE

20-070--72-78      PDS Progressive Shock Spring 59/61/230mm 72-75-78N ORANGE

20-070--75-81      PDS Progressive Shock Spring 59/61/230mm 75-78-81N ORANGE

20-070--78-84      PDS Progressive Shock Spring 59/61/230mm 78-81-84N ORANGE

 

 

 

250/300EXC

250EXCF

350EXCF

450EXCF

500EXCF

 

55-65kg

56

56

56

60

60

 

65-75kg

60

60

60

63

63

 

75-85kg

63

63

63

66

66

Linear

85-95kg

66

66

66

69

69

 

95-105kg

69

69

69

72

72

 

105-115kg

72

72

72

75

75

 

115-125kg

75

75

75

78

78

 

115-125kg

78

78

78

81

81

 

Spring list    Linear

20-070-60     Teknik Shock Spring 59id x 230 x 60N WHITE

20-070-63     Teknik Shock Spring 59id x 220 x 63N WHITE

20-070-66     Teknik Shock Spring 59id x 220 x 66N WHITE

20-070-69     Teknik Shock Spring 59id x 220 x 69N WHITE

20-070-72     Teknik Shock Spring 59id x 220 x 72N WHITE

20-070-75     Teknik Shock Spring 59id x 220 x 75N WHITE

20-070-78     Teknik Shock Spring 59id x 220 x 78N WHITE

20-070-81     Teknik Shock Spring 59id x 220 x 81N WHITE

 

Weight includes 10kg riding gear.

Available from WP.

 

Ohlins Ducati 1098S Fork Kit

Ohlins Fork Piston Superbike Kit for the Ducati 1098S.

Click to download orginal article or scroll down to the bottom.


OHLINS FORK PISTON SUPERBIKE KIT FOR THE DUCATI 1098s

Ohlins Racing has been a vital part of the Ducati success story throughout the years in the Superbike and MotoGP racing series and the heritage continues in the special 1098s version that is equipped with advanced suspension technology from Ohlins to make an even more impressive and potent race bike.

The 1098s version will not only be a fantastic eye catcher at the local trattoria. The bike is born on the race track and many serious racing teams will take the bike back to its roots. For this reason Ohlins Racing has developed a special piston kit for the front fork, and a race setting for the rear suspension. This kit will ease your doubts considerably the next time you look over your digital MotoGP derived cockpit unit, pounding your L-twin 1099cc, 160 Hp full-blood race bike towards the next apex.

Are you going to race your Ducati 1098s? If yes, we got the racing kit for your front fork and rear shock.

OHLINS DUCATI 1098s PISTON KIT

PART NUMBER:

003200-27

PARTS INCLUDED ARE:

  • Compression valve assy 2pcs
  • Rebound valve assy 2pcs
  • Main springs 9,0 N/mm 2pcs
  • Main springs 9,5 N/mm 2pcs
  • Main springs 10,5 N/mm 2pcs

Your Öhlins service center will have a race setting for your shock.

 

Ohlins Rally & Track Owners Manual

Automotive Shocks used for Circuit Racing and Rally Cars.

Click to download original article or scroll down to the bottom.


OHLINS RALLY & TRACK SHOCKS OWNER’S MANUAL

Safety signals

Important information concerning safety is distinguished in this manual by the following notations:

The Safety alert symbol means:

Caution! Your safety is involved.

WARNING!

Failure to follow warning instructions could result in severe or fatal injury to anyone working with, inspecting or using the suspension, or to bystanders.

CAUTION!

Caution indicates that special precautions must be taken to avoid damage to the suspension.

NOTE!

This indicates information that is of importance with regard to procedures.


Introduction

All of Ohlins advanced suspension products are adapted to the specific brand and model. This means that length, travel spring action and damping characteristics are tested individually just for the vehicle that you have decided to fit with Ohlins suspension.

Before installation

Ohlins Racing AB can not be held responsible for any damage whatsoever to suspension or vehicle, or injury to persons, if the instructions for fitting and maintenance are not followed exactly.

Similarly, the warranty will become null and void if the instructions are not adhered to.

WARNING!

  1. Installing a suspension, that is not approved by the vehicle manufacturer, may affect the stability of your vehicle. Ohlins Racing AB cannot be held responsible for any personal injury or damage whatsoever that may occur after fitting the suspension. Contact an Ohlins dealer or other qualified person for advice.
  2.  Please study and make certain that you fully understand all the mounting instructions and the owners manuals before handling this suspension kit. If you have any questions regarding proper installation procedures, contact an Ohlins dealer or other qualified person.
  3. The vehicle service manual must be referred to when installing the Ohlins suspension.

NOTE!

Ohlins products are subject to continual improvement and development. Consequently, although these instructions include the most up-to-date information available at the time of printing, there may be minor differences between your suspension and this manual. Please consult your Ohlins dealer if you have any questions with regard to the contents of the manual.


Design of Ohlins car shock absorbers

Ohlins car shock absorbers are based on Ohlins successful application of the high pressure monotube concept. In short, that means that the damping oil is put under gas pressure, and separated from the gas by a floating piston. The separating piston is positioned in an external reservoir (Fig.1).

To obtain a progressive damping system (PDS), the most advanced shock absorber has two pistons. One of the pistons is active throughout the entire lenght of the stroke, while the second piston begins to work in the event of powerful compression of the shock absorber.

The high pressure monotube concept has many advantages. It prevents the risk of cavitation, that can wear out internal components and cause inconsistent damping. It eliminates aeration of the damping oil, which also causes inconsistent damping. It improves the cooling, because the oil is in direct contact with the outer tubing. It gives more consistent damping, regardless of the shock absorber’s working temperature, and it makes the shock absorber last longer.

The external shock absorber reservoir, connected directly to the shock absorber body or by a hose, is in fact an ”extension” of the main body which contributes to the improved cooling. The reservoir contains the floating piston and the gas that pressurizes the damping oil.

Damping Curves

  1. At low shaft speeds the damping oil is forced through an adjustable bleed valve in the piston shaft. The valve affects mainly rebound damping and has only a small effect on compression damping.
  2. With the bleed valve on the top of the reservoir, you adjust compression damping. The valve restricts the flow to the reservoir, not from it, thereby only influencing the compression damping.

Function

At low shaft speeds the damping oil is forced through an adjustable bleed valve in the main piston shaft. The valve affects mainly rebound damping and has only a small effect on compression damping, see fig 1, graph 1 above. The adjuster is connected to the valve via an aluminium shaft, that runs inside the piston shaft. When the temperature in the shock increases the aluminium shaft extends, thereby closing the bleed valve gradually.

This diminishes the influence of the oil viscosity changes due to temperature, keeping the flow through the valve virtually the same, regardless of temperature.

With the second adjustable bleed valve, on the top of the reservoir, you can adjust the compression damping. Some models have separate high and low speed compression clamping.

The valve restricts the flow to the reservoir but not from it, thereby only influencing the compression damping, see fig 2, graph 2 above.

At higher shaft speeds the damping forces are primarily controlled by the main piston and its compression and rebound shim stacks. By changing the numbers, diameter, and thickness of the shims in the stack and by using different jets in the valves, your Öhlins shock absorbers are tailormade for just your car.

When you are driving

On a smooth surface

When you are driving on a smooth surface and the shock absorbers are compressed slowly (low shaft speed), the damping oil is forced only through the adjuster valve in the piston shaft, (Fig.1), flow 3.

The oil displaced by the piston shaft is forced through the independent compression damping adjuster out into the external reservoir, (Fig.2), flow 3.

The floating piston in the reservoir is forced to move, compressing the gas behind it further. When the shock absorber extends, the pressure behind the floating piston will force the oil through a one-way valve, and back into the shock absorber body, (Fig.4), flow 1 and 2.

The oil beneath the piston returns through the adjuster valve in the piston shaft, (Fig.3), flow 3.

Hitting a bump

When you are hitting a bump the shock absorbers are compressed fast (high shaft speed). The oil can not be forced ”fast enough” through just the valve in the piston shaft. The pressure on the compression side increases and opens the shim stack covering the compression orifices in the piston, (Fig.1), flow 2.

Also, oil displaced by the piston shaft can not be forced ”fast enough” through just the valve in the reservoir. The pressure increases and a shim stack, parallel to the valve, opens, (Fig.2), flow 1 and 2. The floating piston is forced to move, compressing the gas by the displacement of the piston shaft.

When the shock absorber extends, the floating piston forces the oil through the one-way valve back into the shock absorber body, (Fig.3), flow 1 and 2.

The pressure difference over the piston is still high and the flow can not be forced ”fast enough” through just the valve in the piston shaft. The shim stack covering the rebound orifices in the piston opens and the oil returns, (Fig.4), flow 1.

External adjusters

The Ohlins shock absorbers have a low speed compression adjustment knob located on top of the reservoir (Fig.5). Some models even have a high and low speed compression adjustment (Fig.6).

A low speed rebound adjuster is located in the bottom end of the Ohlins McPherson strut. Adjustments are made with a 3 mm Allen key (fig 7).

On the Ohlins shock absorber, the rebound adjustment knob is located at the end eye of the piston shaft (Fig.8).

The temperature compensation system of the rebound adjuster reduces the number of clicks (due to the elongation of the aluminium shaft, as described earlier) when the shock absorber is hot.

Therefore, always make changes from the previous click position without first closing the adjuster.

To count the number of clicks you are using, first let the shock cool down to ambient temperature.

NOTE!

Using too much force when closing the adjuster will destroy important sealing surfaces. When possible use no tool, simply your fingers.

All the adjusters have a normal right-hand thread.

Click position zero (0) is when the adjusters are turned clockwise to fully closed.

WARNING!

There is no stop telling when the adjusters are fully open. It is possible to unscrew the strut rebound adjuster if more than the recommended usable clicks are used. Please see "Setting up your car".

Setting up your car

Installing new shock absorbers may alter ride height, wheel angles etc. on your car. Therefore, it is wise to do a complete resetting of the car after you have installed the Öhlins shock absorbers.

Perform the following steps and always make notes before using the shock absorber:

  1. Check ride height front and rear. Adjust if necessary.
  2. Check corner weight front and rear, if scales are available. Adjust if necessary.
  3. Check all wheel angles front and rear. Adjust if necessary.

Camber bushings

Unlike most standard McPherson struts, the Ohlins struts feature camber bushings that enable you to alter the wheel camber.

The different bushings are marked: bushing type 5194 with grooves; bushing type 5794 with a punched number on the side (last figure of the Part No.).

Depending on how you mount the bushings, with the eccentric hole facing the wheel or away from the wheel, different camber angles will be obtained.

Camber bushings available

Bushing type 5194

Bushing type 5794

Part no.

Marking grooves

Eccentricity in mm

Part no.

Eccentricity in mm

05194-00

0

0

05794-00

3.0

05194-05

1

0.5

05794-01

2.44

05194-10

2

1.0

05794-02

1.88

05194-15

3

1.5

05794-03

1.32

05194-20

4

2.0

05794-04

0.76

05194-25

5

2.5

05794-05

0.20

05194-80*

 

 

 

 

*No hole, the customer can drill the hole to tailor camber exactly.

Recommended settings

The shock absorbers in your kit are adjusted to the Ohlins recommended setting for your car, see Mounting instructions. We advise you to use this as your start setting.

Making suspension settings adjustments

Suspension settings are dependent on your car’s weight, your driving style, road conditions etc. If you are not happy with our recommended settings, here are a few guidelines and ground rules how to make adjustments.

To make improvements, it is important to understand the function of the shock absorbers and through testing learn how they affect the handling of your car.

Always start with the Ohlins recommended settings, see ”External adjusters” and ”Recommended settings”.

When making adjustments; keep notes, make adjustments one at a time and in small steps.

The adjusters should normally not be adjusted in steps of more than 2 clicks at a time and not outside the usable click range.

When you think you have made an improvement, go back to what you started with and double check to be sure. Pay attention to changes in conditions like tires or temperatures, etc.

In general, compression damping changes should be used to influence the car's stability and response, while rebound damping changes should be used to influence comfort and traction.

When you need more damping force, you should mainly try to increase compression damping and use as little rebound damping as possible.

This usually means that you gain comfort and handling performance.

NOTE!

Higher click numbers give less damping force.

Inspection and maintenance

Clean the shock absorbers externally with a soft detergent. Use compressed air. Be careful that all dirt and debris is removed.

Lift the bump rubber and clean the area below.

Keep the shock absorbers clean and always spray them with oil (QS 14, WD40 or CRC 5-56 or similar) after washing the vehicle.

CAUTION!

Never use detergents that can damage the surfaces of the shock absorber. IA thinner and brake cleaner will dry the surfaces too much.

WARNING!

Never alter the gas pressure. Special-purpose charging equipment and access to nitrogen is required. The gas pressure should normally never be altered.

After every competition:

Inspection points:

  1. Check brackets for possible excessive play.
  2. Check the piston shaft for leakage and damage.
  3. Check the shock absorber body and for external damages.
  4. Check the external reservoir for damages that can restrict the floating piston from moving freely.
  5. Excessive wear of rubber components.
  6. Fastening to the vehicle.
  7. Check the hose for leakage and damage.

NOTE!

Make certain that your shock absorber are always filled with Ohlins High performance shock absorber oil

Every 300-500 km (Mc Pherson struts only):

  1. Remove the cartridge from the front outer tube by removing the bottom nut.
  2. Clean all parts with a soft detergent.
  3. Lubricate the the inner tube and the scraper with a layer of Ohlins red grease, part No. 146- 01 (100 grams) or 146-02 (400 grams). The space between the bushings in the outer tube should be filled with a layer of Ohlins red grease up to the bushing surface.
  4. Assemble the strut and tighten all nuts.

Once a year:

Change shock absorber oil. Use only Ohlins shock absorber oil. Contact your Ohlins dealer.

NOTE!

Discarded Ohlins products should be handled over to an authorized work shop or distributor for proper disposal.

Ohlins TPX & TTX 44 Automotive Shock Owners Manual

Automotive Shocks used for Rally, Rally Raid and Rally Cross racing events.

Click to download original article or scroll down to the bottom.


OHLINS AUTOMOTIVE SHOCKS FOR RALLY, RALLY RAID AND RALLY CROSS RACING

Ohlins Racing AB - The Story

It was the 1970th’s, a young man named Kenth Öhlin spent most of his spare time pursuing his favourite sport: motocross.

A careful observer, Kenth’s attention was continually drawn to one specifi c detail - motocross bikes had more engine power than their suspension could handle. It was not long before Kenth realised that better performance could be achieved by improved wheel suspension.

Ohlins Racing was established in 1976, and just two years later the company won its fi rst World Championship title. Despite being in the business for 30 years, the search for perfection and new functions is still the main focus of the company.

Congratulations

You are now the owner of an Ohlins Shock Absorber. More than one hundred World Championships and other major world titles are definitive proof that Ohlins shock absorbers offer outstanding performance and reliability.

Every product has gone through rigorous testing and engineers have spent thousands of hours, doing their very best to use every possible experience from our 30 years within the racing sport.

The product that you now have in your possession is pure racing breed that is built to withstand. By installing an Ohlins shock absorber on your vehicle you have made a clear statement… you are a serious rider with a focus on getting the maximal handling ability and outstanding feedback from your vehicle. Along comes the fact that your shock absorber will be a long lasting friend, delivering the very best of comfort and performance every time you go for a ride.


Safety Precaution

Ohlins Racing AB cannot be held responsible for any damage to the shock absorber or vehicle, or injury to persons, if the instructions for installing and maintenance are not followed exactly.
Similarly the warranty will become null and void if the instructions are not followed.

Safety Signals

In this manual, mounting instructions and other technical documents, important information concerning safety is distinguished by the following notations:

The Safety Alert Symbol means:
Warning! Your safety is involved.

WARNING!
The Warning Symbol means: Failure to follow warning instructions can result in severe or fatal injury to anyone working with, inspecting or using the shock absorber, or to bystanders.

CAUTION!
The Caution Symbol means: Special precautions must be taken to avoid damage to the shock absorber.

NOTE!
The Note Symbol indicates information that is of importance regarding procedures.

WARNING!

  1. Installing a shock absorber, that is not approved by the vehicle manufacturer, may affect the stability of your vehicle. Ohlins Racing AB cannot be held responsible for any personal injury or damage that may occur after installing the shock absorber.
  2. Please study and make certain that you fully understand this manual and the mounting instructions before handling this shock absorber. If you have any questions regarding proper installation procedures or maintenance, please contact an Ohlins dealer.
  3. Refer to the vehicle service manual when installing this shock absorber!

NOTE!
Ohlins products are subject to continuous improvement and development. Therefore, although these instructions include the most up-to-date information available at the time of printing, there may be minor differences between your shock absorber and this manual. Please consult your Ohlins dealer if you have any questions regarding the contents of the manual.
Before riding the vehicle, always make sure that the basic settings made by Ohlins are correct. See the Mounting instructions for recommended Set-up data. Contact an Öhlins dealer if you have any questions about setting the shock absorber.


Design and Function of Ohlins TPX/TTX

Congratulations on choosing the Ohlins TPX/TTX Rally shock absorber - the most unique and powerful racing shock absorber available today. The TPX 44 is of a McPherson type and TTX 44 is of a twin tube type shock absorber. Both are 3 way adjusted. High and low speed compression with Rebound adjusters. Both are available with the new updated Progressive Damping System (PDS). The TPX/ TTX44 shock absorber design is the culmination of two decades of Ohlins successful participation in World Championship events.

This shock absorber draws on all the expertise developed by Ohlins while winning more than a hundred World Championships.

The TPX/TTX44 shock absorbers are designed to handle the demanding damping characteristics needed for all types of tracks, from hard packed soil to soft sand tracks.

The Ohlins TPX /TTX 44 features patented. Pending concept with a unique design that allows for the gas pressure to always back-up the low-pressure side of the piston to keep pressure at a controlled level. Both concepts give the possibility to have totally separated adjusters for compression and rebound damping.

The temperature stability is maintained by using a flow restriction design in the bleed valves that create a turbulent flow at very low piston velocities. Also, materials with different thermal expansion rates are used to compensate for the viscosity change of the fluid caused by changes in temperature.

The Ohlins shim system offers infinite combinations of shim stacks with a wide spectrum of different character with one and the same piston. The whole system is pressurized by nitrogen gas behind a floating piston to ensure separation of the gas and fluid.

The Ohlins TPX/TTX44 shock absorbers are a racer friendly shock absorber, easy to set up, dial in and rebuild. Support is always available from the Ohlins distributors worldwide.

Spring Preload

Spring Preload

When adjusting the spring preload you move the spring seat. This will lower or raise the vehicle ride height. The ride height is an important criteria for the behavior of your vehicle.

Set the Spring Preload

For TTX shock absorber use C-spanner 00710-02 and C-spanner 01796-01 to undo the lock nut and turn the spring platform to the desired position.
For TPX McPherson use 2 C-spanners 01796-01 to undo the lock nut and turn the spring platform to the desired position.

Compression and Rebound Damping

Function and Reset

Compression and Rebound Damping

Compression damping controls the energy absorption when the shock absorber is being compressed, thus controls how easy the shock absorber compresses when you hit a bump.

Rebound damping controls the energy absorption when the shock absorber is being extended and controls how fast the shock absorber returns to its normal position after being compressed.

The TPX compression adjuster is located under the reservoir and the rebound is located in centre at the bottom of the damper.

The TTX compression and rebound adjusters are located on the cylinder head close to the reservoir.

To reset the adjuster

Turn the adjuster clockwise to fully closed position (position zero [0]). Then, turn counter clockwise to open, and count the clicks until you reach the recommended number of clicks. See recommended Setup data in the Mounting Instructions for each shock absorber/strut.

CAUTION!
Do not use force, delicate sealing surfaces can be damaged. Handtighten only.

Compression Damping Adjuster

Low speed compression is mainly used to control chassis movements and response but it also affects the traction. It affects how the car behaves during breaking, turn in and acceleration. Less low speed compression gives more chassis movement but in many cases it can improve traction and grip. Therefore it is possible to balance the car by adjusting the low speed compression.

High speed compression mainly affects how the car absorbs bumps and jumps. In rougher conditions or with a lot of jumps more high speed damping is often necessary to control the big chassis movements.

Rebound Damping Adjuster

Rebound adjuster affects chassis movement in a similar way as the low speed compression but has even more influence on traction. Use this adjuster to control chassis movements over crests or after jumps. More rebound gives less movement and better stability but too much will cause a loss of traction. It is therefore a powerful balance tool together with the low speed compression adjuster.

For slippery conditions when grip levels are low, a softer set up on both rebound and low speed compression is a way to gain more traction.

Adjustments

Compression and Rebound Damping

Rebound Damping Adjuster

Rebound damping on TTX 44 is adjusted by turning the golden slotted screw located in the black end-piece. Total number of clicks on the rebound adjuster is approximately 18-20.

Rebound damping on TPX 44 is adjusted with the special tool (01822-03) which is delivered with the damper. The total number of clicks is more than 60 but the useful range is 20-40. It is recommended to adjust rebound in steps of 2-3 clicks.

Compression Damping Adjuster

Low speed compression is adjusted by using a 3mm Allen key.

High speed compression is adjusted with a 12 mm wrench.

It is recommended to adjust low speed compression in steps of 2-3 clicks and high speed 3-5 clicks to fi ne tune the set up. The low speed adjuster has approximately 40 clicks and high speed 50 clicks.

Adjustments

Shaft jet valve and Spring set-up

Shaft jet valve

On the TTX the fading compensation system is located in the piston shaft. This system is based on a valve that compensates for the viscosity changes of the fluid caused by changes in the temperature.

The shaft jet valve adjuster is set at an ideal position (18 clicks) from the factory. However, if the limit of the rebound adjuster has reached its minimum or maximum recommended position, is there a possibility to compensate this by either open or close the shaft valve and then go back on the rebound adjuster.

This adjuster is very sensitive and should not be turned more than 1- 2 clicks without consulting an Ohlins service center. The reset procedure for this adjuster is the same as for the compression and rebound adjusters.

Spring set-up

A number of springs are available for both gravel and Tarmac to suit all different conditions. For rougher gravel conditions it is recommended to use one step stiffer springs but also increase ride height 10-20 mm depending on the conditions. It usually gives a better result than to use an even stiffer spring and less ride height change.

For very rough conditions like Middle East rallies even stiffer springs is recommended.

To get support, to find your own optimal set-up, contact your local Ohlins Service Centre. Ohlins also have got a wide assortment of springs. For specific springs to your vehicle please see list in the Ohlins mounting instruction.

Adjustments

Setting up your vehicle and making adjustments

Setting up your vehicle

Installing new shock absorbers may alter ride height, wheel angles etc. on your vehicle. Therefore, it is wise to do a complete set-up check of the vehicle after you have installed the Ohlins shock absorber.

Perform the following steps and always take notes before using the shock absorber;

Check ride height, front and rear. Adjust if necessary.

If scales are available check corner weight, front and rear. Adjust if necessary.

NOTE!
Always consult your Ohlins dealer if you have any questions regarding settings of the shock absorber/strut.

Making adjustments

Suspension settings are dependent on your vehicles weight, you’re driving style, road conditions etc. If you are not happy with our recommended settings, here are a few guidelines and ground rules how to make adjustments.

To make improvements, it is important to understand the function of the shock absorbers and through testing learn how they affect the handling of your vehicle.

NOTE!
Always start with the settings recommended by Ohlins.

NOTE!
Higher click numbers give less damping force.

When making adjustments:

  • Take notes, make the adjustments in small steps (2-3 at a time) and not outside the usable click range. See mounting instructions.
  • When you think you have made an improvement, go back to what you started with and double check to be sure.
  • Pay attention to changes in conditions like tires or temperatures, etc. In general, compression damping changes should be used to influence the vehicle’s stability and response, while rebound damping changes should be used to influence comfort and traction.
  • When you need more damping force, you should mainly try to increase compression damping and use as little rebound damping as possible. This usually means that you gain comfort and handling performance.

Camber Bushings

Camber bushings

Unlike most standard McPherson shock absorbers, the Ohlins shock absorbers feature camber bushings that enable you to alter the wheel camber.

Depending on how you mount the bushings, with the eccentric hole facing the wheel or away from the wheel, different camber angles will be obtained.

Camber bushing identification

The bushings are as follows:

Part.No

Marking

Distance (A) mm

05794-00

0

3,00

05794-01

1

2,44

05794-02

2

1,88

05794-03

3

1,32

05794-04

4

0,76

05794-05

5

0,20

 

Inspection and Maintenance

When and how?

Inspection points - Normal use

  1. Check ball joints/ brackets for possible excessive play or stiction.
  2. Check the piston shaft for damage that can cause leakage.
  3. Check the shock absorber body for external damage.
  4. Check the external reservoir for damage that can restrict the floating piston from moving freely.
  5. Make sure that the reservoir is protected against stone chip.
  6. Check the attachment of the shock absorber to the vehicle.

    
Inspection points - Every 300-400 km (Mc Pherson shock absorber only)

  1. Remove the scraper holder from the outer tube with a suitable friction tool. Cover the circlip groove at the top of the cylinder tube with tape and pull the scraper holder off the cylinder tube - see figure.
  2. Remove the cartridge from the front outer tube by removing the bottom screws.
  3. Clean all parts with a soft detergent.
  4. Check scraper and bushings for wear and/or damages and change if necessary.
  5. Apply a layer of Ohlins red grease, part no. 00146-01 (100 grams) or 00146-02 (400 grams) on the cylinder tube, scraper and bushings. The space between the bushings in the outer tube should be filled with a layer of Ohlins red grease up to the bushing surface.
  6. Assemble the strut and tighten all bottom screws (10 Nm). It is vital to use copper paste on the threads.
  7. Install the scraper holder on to the outer tube and handtigthen with a suitable friction tool. Tightening torque maximum 15-20 Nm.

Maintenance

Service your damper(s) at an Ohlins service center every 800-1200 km. If the dampers are used under more rough conditions, maintenance could be required more frequently.

WARNING!
Never alter the gas pressure. Special purpose charging equipment and access to nitrogen is required. The gas pressure should normally never be altered.

 

bike setup guides

Whether you want a lap time advantage over your competition offroad or on track, want to make those long roadtrips more comfortable, or anything in between, our Setup Guides can teach you how to make all those seemingly complex adjustments with ease.

Free Suspension Setup Tips

Can you set up a bike’s suspension without spending a cent? You can if you know where to look…

Click to download orginal article in Australasian Dirt Bike Magazine or scroll down to the bottom.
Courtesy of Australasian Dirt Bike Magazine.


Can you set up a bike’s suspension without spending a cent? You can if you know where to look…

One of the most overlooked aspects of increasing a rider’s performance is suspension. A quick bike is one thing, but if it handles like a three-wheeled billycart or smacks the rider around like a naughty nurse, all that perceived performance is lost. You’ve got to get it handling.

Your shiny new bike is delivered with a standard set-up for the average rider, whoever that is. Properly understanding the basics of suspension and how to adjust them using the built-in (on most bikes) adjustable suspension is the key. Accurate suspension adjustments make direct improvements to traction, control and comfort. This can’t be overlooked.

In the first part of a two-part series, we look at optimising what you have without cracking the credit card and offer some good, basic starting points. A better ride is just a read and 30 minutes in the garage away!


BIKE SUSPENSION SETUP BASICS

Before reaching for a screwdriver, you have to understand the basic components. Both the fork and shock have two key elements: the spring and damping. The spring is load- or position-sensitive; its job is to hold the rider’s and machine’s weight. The dampening – which is what the clickers control – is a speed-sensitive element.

The spring is really just a piece of metal that’s bending. It’s like a trampoline: if you stand on a trampoline, it holds you up; but if you jump on it, it compresses and then rebounds with equal force. If you just had a spring on a motorcycle – and no dampening – it would be like a car going down the freeway without shocks; it would pogo like a, er, pogostick.

Adding dampening to the suspension is like putting that trampoline in water. It will still support your weight, but you don’t get the springy, bouncing effect. Of course, there’s no need to dump your trampoline into the pool to see what I’m getting at…

SUSPENSION ADJUSTERS OR CLICKERS

FORK:

The compression (C) clicker or adjuster is usually at the base of the fork; sometimes covered by a rubber plug; just flick it out with a screwdriver (the reverse is true for Showa, Kayaba and WP twinchamber forks where it’s on the top). Rebound (R) is the top clicker for all forks other than twin-chamber forks. The clickers should be clearly marked if you’re not sure.

SHOCK:

The low-speed compression (LSC) clicker has a flat blade screwdriver fitting at the top of the shock.

For high-speed compression (HSC) there’s a large red hex nut at the top of the shock (it moves independently of the low-speed) For rebound (R), the adjuster at the bottom of the shock.

SUSPENSION ADJUSTERS OR CLICKERS?

A suspension unit, fork or shock absorber (damper) will have oil-controlled dampening in both directions: compression, sometimes called “bump” when the unit is compressed; and rebound, when the spring pushes the damper back out to its original height. The system of dampening has evolved from a simple series of holes that oil was pushed and pulled through to a pressurised valving system, comprising pistons, shims, bleeds, etc.

The term “clicker” refers to the external adjuster that will change the dampening force. Think of a clicker as you would a garden tap. The more you open up the tap the more water flows. The tap is more sensitive the closer it is to being closed, i.e. from half a turn to one turn produces a big change in water flow. Five to six turns does very little. This is an oversimplification, but you get the idea.

In the damper, an adjuster uses a tapered needle and seat. There are different tapers on needles and different orifice sizes but they all work the same way – to bleed oil away from the main dampening devices in the damper. So, turning the clicker in (clockwise) will produce more dampening force, conversely turning the adjuster out means less dampening. This applies for both compression and rebound.

SPRINGS

As the springs support mass, this keeps the motorcycle’s geometry as the manufacturer intended. The “average” target weight for a full-size motorcycle is generally a 75-80kg rider. You can do an easy check, commonly known as a sag test or ride height test to determine where you are. I’ll explain the rear only as the front is quite difficult to do as the fork seals will drag and interfere with the results. It’s best to strip the forks and do sag heights dry if you really want to check the forks. There is no way a manufacturer can know what you weigh, hence the adjustability – which only works if you use it. On most offroad motorcycles there is a threaded collar on the shock body which provides easy adjustment to spring “preload” on the shock.

SET YOUR SAG

To set your sag (see the sidebar for information on where to start), raise the machine off the ground on a stand and wind the clickers all the way to full soft so they don’t interfere with the results. Measure from the rear axle to any fixed point on the rear sidecover or muffler. You might find it easier to make a mark with a felt tipped pen at a convenient number. We’ll use 500mm as an example. You need to be quite accurate as a few millimetres will make a difference.

Put the machine back down on the ground and have the rider sit in their normal riding position. Wearing riding gear is preferable but you can estimate the measurement by adding 5mm to account for the extra weight. In our example, the measurement is now 380mm; therefore we have a ride height, or rider sag, of 120mm (500 minus 380mm). Get the rider to stand and repeat the measurement. Then use the average of the two measurements.

Lastly, we measure the height with the rider off the machine, to determine how much the machine sags under its own weight. We have measured 480mm, meaning we have 20mm of “static” sag. If the machine we are measuring is a motocross bike and we require 100mm rider sag, we would need to wind a lot more preload onto the rear spring to achieve this. However, as we only have 20mm static sag if we wind more preload on we will have no static sag, so we need to go to a stiffer spring. See the table (right) for a general guideline.

SAG STARTING POINTS

 

125/250/450 MX and Enduro 300+mm suspension travel

80/85cc

Mini MX

50/65cc

Mini MX

KTM PDS

XR250, 400,

600,650,

KLX250/300

DR-Z,KLX 400

Front static sag

30 +/- 10mm

15 +/- 5 mm

15+/- 5mm

30 +/- 10mm

30 +/- 10mm

30 +/-10mm

Front ride height

50 +/- 10 mm

40 +/- 5 mm

30+/- 5mm

50 +/- 10 mm

50 +or- 10 mm

50 +or- 10 mm

Rear static sag

30 +/- 10 mm

10 +/- 3 mm

10+/- 5mm

30 +/- 10 mm

25+/- 5mm

25+/- 5mm

Rear ride height

100 +/- 3mm

85 +/- 3 mm

65 +/- 5mm

113 +/- 5-15mm

85+/- 3mm

90+/- 3mm

 

Notes:

  • The PDS system is a little different. We suggest 113-118mm ride height to begin with; however 95-120mm is a practical working range, all with 35mm static sag.
  • Machines with less suspension travel like the Suzuki DR650 use 85mm rear ride height.
  • Soft springs require more preload, hard springs less preload. Final selection is not only dependent on final figures but also personal preference. Very often a firmer spring rate will be more compliant in the first part of the stroke because it requires a lot less preload for a given ride height.
  • If you have too little static sag for the correct ride height, the spring is too soft. Too much static sag and the spring is too hard. Seems backwards huh? It’s not. Don’t fret if you can’t get it perfect, at least you will get closer to ideal and you can always fit a heavier or lighter spring later.

CLICKER STARTING POSITIONS

Often I will call a client on Monday after a race to see how he (or she) went. Occasionally, I am met with the response of “it was too soft” or “it was too stiff”. My next question is: “What clicker position did you start out at and where did you end up? Did the adjustments you made help?” Sometimes, the answer I get is: “I didn’t touch them; I left them right where you put them.” Hmmm.

So, before we launch into how to make the best of what you have, write down where your clickers are now. Take a screwdriver and count the clicks in to full hard (clockwise) and write them all down. If you are lost, 10 to 12 clicks out on everything is a good place to start, or look in your manual. This way, if you get lost in the next section, you can always go back to your starting position.

TRACK STARTERS

Hardpack to intermediate terrain tracks:

Set the compression softer, (turn clicker out) front and rear to help get maximum wheel contact and plushness.

Sand tracks:

More low-speed compression and rebound is necessary. Start by adding 1-2 clicks (turn clicker in) of rebound and as the track gets rougher, add compression 1-4 clicks (turn clicker in). Harshness is a result of “packing” in the fork. Remember to add compression (turn clicker in) to help keep the front-end from “packing”. The rear suspension will exhibit packing by swapping. To eliminate swapping begin adding compression (turn clicker in) until the bike tracks straight and then add rebound (turn clicker in) to keep the rear following the terrain of each whoop. Don’t be concerned if your clickers are nearly maxed out in sand conditions. Unless, of course, you had your bike revalved for sand.

Supercross: (G-load, curb hits)

G-loads produce slow piston speeds. This means that less dampening is produced by the shock and forks in a situation that causes more of a bottoming load. To set your bike up for supercross, adjust the compression stiffer (turn clicker in) on the suspension (2-6 clicks) and in some circumstances raise oil level and/or change to stiffer springs. In reality, no stock motocross bike suspension can handle SX, internal changes are required.

SHOCK SETTINGS

Setting rebound damping:

Find a relatively fast straight with braking bumps leading into a corner. Reduce (wind clicker out, two or three clicks at a time) the rebound damping until the rear-end begins to hop or feel loose. Then increase (wind clicker in) damping until the sensation goes away.

Find a jump that tends to pop the bike up off the ramp. The rear-end should absorb and then smoothly lift the motorcycle into the air. If the rear-end bounces up, slow the rebound (wind clicker in).

Find some large whoops. The bike should track straight through the whoops with the rear wheel extending to the ground before the next impact. If it does not perform as described above, it is packing (not rebounding fully) and the rebound damping should be reduced (wind clicker out, except in sand).

Setting compression damping:

Find a corner with acceleration bumps on the exit. The rear of the motorcycle should follow the ground. If the rear-end “breaks up”, soften the compression. (Turn clicker out. If this fails, speed up the rebound two clicks).

Find some rough sections, a large jump and a couple of G-outs. The shock should bottom on the roughest section but it should not be a slamming sensation. Add compression to fight bottoming (turn clicker in). But avoid going too far as small-bump ride will be sacrificed in the trade. Remember, the adjusters have a primary effect on the low speed, so even a large change in setting may only affect bottoming resistance slightly. Remember bottoming your suspension is not necessarily a bad thing. You should strive to bottom off the biggest bottoming load obstacle on the track. If you don’t you’re not getting maximum plushness from your suspension.

FORK SETTINGS

Setting the compression:

The fork should react to all track variations. If the fork seems harsh on small bumps or holes, soften the compression (wind clicker out). If it isn’t, slow compression (wind clicker in) until they do feel harsh and then turn back a click or two. Now find the rough part of the track again. The forks should bottom over the worst obstacle. If harsh bottoming occurs, add oil in 5ml increments.

Setting the rebound:

The rebound damping is responsible for the stability and the cornering characteristics of the motorcycle.

Find a short sweeper. When the fork compresses for the turn, the speed at which the fork returns is the energy that pushes your front wheel into the ground. If the fork rebounds too quickly, the energy will be used up and the bike will drift wide, or wash. If the rebound is too slow, the bike will tuck under and turn too soon to the inside. Find the appropriate balance for each track.

With the bike turning well, the wheel should return to the ground quickly yet not deflect off berms or bounce off jumps.

You can now get the best from your standard suspension and it’ll only cost you a bit of time and trial and error. If that’s not enough, it’s time to crack the fork caps. Stay tuned for Suspension Part Two!

 

 

Road Bike Setup Guide

Our detailed Suspension Setup Guides help you get the most out of your Road bike, whether modified or stock.

Click to download original article or scroll down to the bottom.


GET THE MOST OUT OF YOUR ROAD BIKE WITH TEKNIK'S SUSPENSION SETUP GUIDE

ABOUT TEKNIK

Teknik Motorsport is a manufacturer and importer of motorcycle suspension products. We also have a workshop dedicated to developing and testing new products. Teknik is a family owned Australian company that is enthusiastic about motorcycling and is staffed by people who are passionate motorcyclists, and our products are manufactured in Australia wherever possible.

Teknik has been operating since 2001. We have been involved with Enduro legend Geoff Ballard, and the Ballards Yamaha Offroad team from 2001 and Lyndon Heffernan’s Academy Of Off-Road Riding since 2003. We have also built the suspension for the GHR Honda Off Road Team, in Enduro, off road and the Australian Safari, culminating with an outright win in the 2004 Safari.

In 2006 we ran two Kawasaki KX250F’s in our own MX Nationals Pro Lite MX team in conjunction with ADB magazine. A solid success, and team rider Mike Phillips has since gone on to much higher success.

For 2007/2008 we went road racing, attending every round of the ARRC, supporting a number of privateer riders in the Supersport class, and we performed major setup and development work for Craig McMartin on the 1098 and 1198 Ducati in Pro Twins. How’d he go? Two more CHAMPIONSHIPS! Lap records at every track, and nearly 2 seconds off his PB around his home track of Eastern Creek. Thats a win for Teknik and a win for you as all our development work from the track goes into your suspension.

All our parts and kits have been extensively tested in the field by both our own race team and riders we support.

INTRODUCTION

Today’s motorcycles are very advanced. Gone are the days of the owner having to finish the manufacturing. However, they are not perfect, they never can be. The nice folks who build your bike don’t know you. They don’t know if you weigh 60 kilos or 120 kilos. They don’t know whether you carry a bunch of gear, or a pillion. They don’t know where you ride or how you ride it.

Getting your suspension dialled in for your riding style is one of your first priorities when you take your new bike out on the track. However, it is an on-going process, and what worked today might not suit the next track conditions you encounter next week. Therefore, you have to take on the role of test rider yourself and learn to identify problem areas. Never stop testing and thinkingabout what your bike is doing. Read your owners manual too, it’s full of good stuff.

This booklet is full of practical information that can help people with both revalved or standard suspension, and has been complied from archival material, conversations with race engineers, input from Suspension Tech NZ and our own ongoing experience working with top riders throughout Australia.

The figures we have come up with have generally worked very well but individual riders may get better results with alternative personalized settings. Our experience and personal education is ongoing and we hope these notes will assist in your set up, speed and safety. We will continue to offer our on track service at selected meetings and continue to develop our settings to the benefit of our clients.

When using this manual, it is intended that you start at the clickers section and work your way through. It is of little use making suspension and geometry adjustments when you have no idea of the basics: where your clickers are, ride height, springs rate, shock length. Remove the set-up sheet at the back of this manual and photocopy it. Keep the notes as a record for each track, and to give you direction when reviewing settings. If you don’t keep records, you will chase your tail all weekend.

To get started, I’ve included a quote from Ross Maeda of Enzoracing in California. Ross has a way of making complex systems seem simple…

“To understand how to start adjusting your suspension, you have to understand the basic components. Both the forks and shock have two key elements: the spring and dampening.
The spring is load or position-sensitive, which basically means it’s job is to hold the rider’s weight.
The dampening -- which is what the clickers control -- is a speed-sensitive element.
The spring is really just a dumb piece of metal that’s bending. It’s like a trampoline, if you stand on a trampoline, it holds you up; but if you jump on it, it goes down a lot deeper and throws up equally as high. If you just had a spring on a motorcycle -- and no dampening -- it would be like a car going down the freeway without shocks; it would bounce up and down for miles.
Adding dampening to the suspension is like putting that trampoline in water. It will still support your weight, but you don’t get the springy, bouncing effect.”

CLICKERS

Note: All clicker settings are referred to from the fully hard (clockwise) position.

Often we call a client on Monday after a race to see how they went. Occasionally we’re met with the response “it was too soft” or “it was too stiff”. Our next question is always “What clicker position did you start out at and where did you end up?

"Did your adjustments help?” Sometimes the answer is:
“I DIDN’T TOUCH THEM, I LEFT THEM RIGHT WHERE YOU PUT THEM.”

Anyone who knows a suspension tuner will realise how much this drives them nuts. Find your suspension’s adjusters (commonly called clickers), and adjust them yourself. One adjustment at a time so you know what it is doing. Keep a note of where you started form, so if you get lost you can go back.

Adjusters are like a tap, closing off the tap to restrict the flow of oil and produce a firmer dampening character. When we turn the adjuster we are not adjusting the valving! We are simply changing the quantity of oil that bleeds past the valving. If you have the wrong valving setting for your application, you will not get an optimum set-up by just turning clickers, however you can improve the motorcycle and make it “the best it can be”. Likewise, even with a perfect shock specification, poor clicker settings will ruin the whole farm.

Turn the adjusters clockwise, counting the clicks or turns. Be gentle; don’t keep turning the screw or knob once it stops. Turn the adjusters back out to the original position. Write the number of clicks or turns down on the set-up sheet.

If in doubt, 10C (compression) and 10R (rebound) is a good place to start for forks with over 20 clicks total adjustment. 1 ½ turns for those forks with no clicks. Units with less total clicks, use a midway position.

For Shocks, again check they are in the suggested positions, and if in doubt, 1 turn out HSC,10 LSC, 10 R are good places to start for most dampers.

BASIC GEOMETRY

This can be broken down into sections.

  • Fork travel / length, usually left standard.
  • Fork height, the position of the fork in the triple clamps. This can be measured in lines above the top triple clamps. I personally prefer to measure length of fork between the bottom of the lower triple clamp and the end of the fork tube. This eliminates the question of do we measure from the front of back of the clamps and gets you used to making small changes, as one line on the clamps will often be 3mm
  • Triple clamp offset and rake, again usually left standard.
  • Rear shock length, including any raising spacers. A tremel bar is perfect for this. Measure the shock out of the bike with a spring on it to compress the internal top out spring
  • Linkage adjustments (or different length pull rods)
  • Swingarm length.
  • Tyre height if you use different profiles.

Forks:

  • Compression (C): For Closed Cartridge forks; Clicker is at the top of the fork. For Open Cartridge forks; Adjuster is at the bottom of the fork, sometimes covered by a rubber plug.
  • Rebound (R): For Closed Cartridge forks; Flat blade screw at the base of the fork. For Open Cartridge forks; screw is at the top of the fork.

Shocks:

  • Low Speed Compression (LSC): Flat blade screwdriver fitting at the top of the shock.
  • High Speed Compression (HSC): Large hex nut at the top of the shock (it moves independently of the low speed). Some brands have clicks, others you need to count turns
  • Rebound (R): Flat blade screwdriver fitting at the bottom of the shock

SAG

Before you start making adjustments it’s best to know where you are starting from. First job is to check the suspension sag settings. This will allow you to check if you have the right springs and get used to making some adjustments. Often OEM springs will loose some free length over time, so if you feel the motorcycle is not handling how it did, recheck the sag.

Determine the fully extended height of the suspension. This can only be checked with both front and rear wheels off the ground. If you have access to stands it makes life easier. Use a fixed point at the rear sub frame, not the rear ducktail as it can move around. Measure from the rear axle straight up, vertically. Wind all the clickers to full soft so dampening forces don’t cloud the results. You need to be accurate as a few mm make a difference.

Next have the rider sit on the machine in his or her riding gear.

The first measurement minus this measurement will give us ride height (also known as rider sag).

As an example; if our first measurement was 500mm and this measurement is 460mm we therefore have 40mm of rider sag.

Lastly, measure the amount the machine sags under it’s own weight with no rider. If you subtract this measurement from the first, you will have static sag.

In our example, this measurement is 490mm, we subtracted from our original 500mm to get 10mm of static sag.

In our example, the machine we are measuring is a Superbike with a top out spring, and we require approximately 30mm rear rider sag, wind some more preload onto the rear spring to achieve this. However as we only have 10mm static sag, if we wind more preload on we will have no static sag, so we need to go to a stiffer spring.

  • If you have too much rider sag or too little, increase or decrease the amount of spring preload to get it closer.
  • Then if static sag is correct, Rider sag less than minimum – spring is too firm (or if rider correct & static more than max)
  • Static sag correct, rider sag more than max – spring is too soft (or if rider correct & static less than min)

See the following tables for a general guideline.

FORK SAG

 

Supersport / Superbike with Ohlins (no Top Out Springs)

Supersport / Superbike

with Top Out Springs

Road / Race 125 / 250

Static Sag

25 - 28 mm

20 - 23 mm

15 - 20 mm

Rider Sag

+ 10 - 13 mm

+ 10 - 13 mm

+ 10 - 13 mm

 

Note:

  1. Many front forks have internal top out springs which will influence the best ride height and settings.
  2. Many OEM front forks require a higher initial ride height because mid valve tension is generally ‘soft’ allowing forks to ‘blow’ through their stroke too readily. Where mid valve tension is increased, Ohlins type settings can be used.
  3. Excessive pre-load on overly soft front fork springs will cause harsh feel and poor mechanical grip.
  4. On most forks setup for racing they will have zero preload on the fork springs with the preload adjuster backed all the way off and the top-out springs fully compressed. Most preload adjusters have a 1.0 mm pitch thread so 1 turn of the adjuster is 1mm of preload.
  5. “Normal” preload range is 3 - 14mm. Lighter springs require more preload, heavier springs require less.
  6. For a given rider there will usually be 2 or perhaps 3 spring rates that could be used, depending on the track. For example, if you ride a Supersport machine and use 0.90 kg/ mm springs at rough tracks like Broadford in Vic, but the high speeds and g-forces of Phillip Island may demand 1.00 kg/ mm, while you find at Eastern Creek that 0.95 kg/mm works best. All 3 sets will come into the commonly accepted adjustment range or rider sag and static sag.
  7. To minimize front fork stiction (commonly used term to describe the level of force needed to over come friction) it is very important that axle pinch clamps are only tightened after the forks have been compressed several times to ‘neutralize’ their position. Failure to do so can sometimes result in substantial stiction.

REAR STATIC SAG

- See notes on Top Out Springs

 

Supersport / Superbike

Road / Race 250

Road / Race 125

With Top Out Spring

10 - 15 mm

5 - 10 mm

-

Without Top Out Spring

5 - 10 mm

0 - 5 mm

Just Top Out 0 mm

 

Note: Road/Race 125’s cannot afford to lose the momentum that sag would give in a straight line (loss of top speed). Fairing ‘attitude’ is everything.

REAR RIDER SAG

- Equates to normally 1/3rd of full stroke as a starting point

 

Supersport / Superbike

Road / Race 250

Road / Race 125

With Top Out Spring

27 - 32 mm

22 - 27 mm

-

Without Top Out Spring

22 - 27 mm

17 - 22 mm

15 - 20 mm

 

Note:

  1. The above settings are guidelines only, and some riders may have better ‘feel’ and speed with alternative settings.
  2. As with the forks there are usually 3 spring rates that can be used and still be “correct”. We suggest that you measure your springs off the shock and then measure the installed length so you know the preload in mm. For example, if you are using a 90Nm shock spring but wish to fit a 95Nm spring, and you know that you are using 13mm of preload on the 90Nm spring then a reduction of 1mm in spring preload to 12mm will get you a similar starting point to maintain geometry but the 95Nm will “ramp up” more as you use more travel.
  3. Many, but not all, Ohlins racing shocks feature and internal top out spring. The reason for this spring is to give a little more extension travel under braking as the weight of the machine is transferred forward. This allows the rider to go into the braking area a little deeper before the rear end starts to unload. These springs are usually available in 3 rates; soft, medium and hard. Selection is dependant on such factors as spring rate, machine weight and as a tuning tool for rider preference. Some of the top riders actually prefer to run a positive stop with no top-out spring as the more abrupt stop allows them to initiate a slide in, more commonly known as “backing it in”. When measuring rear shock sag you must first determine if your shock is equipped with a top out spring. Check with your Ohlins representative whether your Ohlins shock is fitted with a top out spring.

TRACKSIDE NOTES & LINKAGES

The art of making a motorcycle work at a particular track is made easier when you consider it’s largely the front to rear balance that is being adjusted, varying the weight carried by either the front or rear wheels.

If we increase the rear spring preload 1mm we are putting more weight on the front tyre. If we move the forks down in the triple clamps we are not only decreasing the rake, but increasing the trail and putting more weight on the rear! Everything is related.

For example by simply adding 1 tooth to the rear sprocket we can upset the whole motorcycle. In adding the tooth we may have to lengthen the chain, moving the rear wheel back. This increases the leverage on the rear shock, effectively reducing the spring rate. The longer wheelbase will typically make the machine more stable, but probably slower to turn. We may now have a tyre tearing issue that is not from the lower gearing.

Keep notes on the changes you make.

Issues such as running wide mid turn are related to the front to rear balance; however it is not easy to determine whether it’s too much weight on the front or not enough! Only making a change and noting its positive or negative character will keep you moving forward.

STOCK SHOCK LINKAGE SYSTEMS

Don’t let the salesman fool you into thinking that this year’s “new model” has overcome all the faults of last year’s. Linkages and stock rear shock settings are a classic example.

Standard springing is a necessary compromise because riders come in all shapes, sizes, expectations and weights. Add to that the possibility of an occasional pillion!

To counteract suspension bottoming through a high load situation the usual approach is to make the second half of the linkage very stiff, maintaining some form of crude ride height control.

LINKAGE FORCE vs TRAVEL

The dramatic increase in the linkage force suits the occasional blast down the road with a pillion, but does create an interesting problem for road racing: You don’t road race with a pillion!

If your chosen spring rate is too soft the suspension will blow through its stroke (especially on bumpier circuits, i.e. Oran, Broadford, Wakefield) and arrive at the “hard” part of the linkage ratio. The suspension will suddenly become very firm, causing overloading of the tyre. As the tyre will now be performing an unfair amount of the suspension work, its contact patch will distortthe carcass inwards, causing shearing of the tyre surface. This can be mis-diagnosed in colder climates as cold shearing.

Production bikes are compromised by having to run the stock linkage, so the approach to the problem is to spring and valve the shock so it does most of its work in the first 1/3 to 1/2 of the travel, keeping it away from the harsh part of the travel. Each model will react differently to changes.

If you are having a shearing problem, the answer is most commonly to increase the spring rate and/or preload and perhaps the compression valving spec. Don’t blame the tyre before time!

SPRING RATES & DAMPING

SPRING RATES

FRONT SUSPENSION

Too Firm can cause:

  • Hard to turn in
  • Good Braking Performance
  • Understeer - pushing the front
  • Feels harsh in corners

Too Soft can cause:

  • Poor braking performance
  • Easy turn in
  • Front can tuck under, or feels like it wants to
  • Tearing of the front tyre

REAR SUSPENSION

Too Firm can cause:

  • Rear feels harsh
  • Poor traction
  • Lack of compliance
  • Tyre looks polished

Too Soft can cause:

  • Good acceleration / traction – sometimes
  • Understeer at corner entry - sitting low
  • Light front end feeling - Wheelstands out of corners (small increases of spring preload can help this)
  • Too much suspension travel - pitching making it difficult to flick bike from one side to the other

COMPRESSION DAMPING

FRONT SUSPENSION

Too much Compression can cause:

  • Good result during braking
  • Feels harsh over bumps
  • Pattering mid corner

Too little Compression can cause:

  • Strong diving on the front
  • Unloads the rear too early causing loss of grip

Note:

Front end compression adjustment should harmonize with the front fork oil level.

REAR SUSPENSION

Too much Compression can cause:

  • Rear wheel slides under acceleration
  • Harsh ride over bumps, poor ‘hook-up’

Too little Compression can cause:

  • Rear wheel starts to bump sideways under acceleration out of corners
  • Bike will squat too much under power and cause front end to lose grip

REBOUND DAMPING

FRONT SUSPENSION

Too much Rebound can cause:

  • Oversteer
  • Poor front tyre grip
  • Front wheel feels like it is tucking under

Too little Rebound can cause:

  • Understeer
  • Front end feels unstable like it is floating

REAR SUSPENSION

Too much Rebound can cause:

  • Rear jumps on bumps instead of following the surface
  • Holds the rear down, causing understeer
  • Overheats shock, causing fade

Too little Rebound can cause:

  • Rear tops out too fast under braking causing rear wheel to lose contact with the ground
  • Bike feels unstable as if it is floating

FORK OIL LEVEL

OIL LEVEL RAISED: Forks are firmer towards the end of the stroke

OIL LEVEL LOWERED: Forks are softer towards the end of the stroke

FRONT FORK AIR GAP

There are 2 forms of spring in every fork, the wire coil springs, and the air trapped in the fork above the oil. Both springs are sensitive to their position in the stroke, but not to speed (the dampening character is sensitive to the speed the fork compresses but not to position).

If you are using linear or straight wind springs, they will provide a linear progression in stiffness as the fork compresses. The air spring or air gap character is not linear; it has little influence in the first 1/2 of the stroke, but has a dramatic influence in the last 1/3. Too low and the fork will bottom too easily, too high and the fork will loose it’s compliance in the last part of the stroke, particularly noticeable on transition from braking to corner entry.

BOTTOMING OUT DEVICES - HYDRAULIC & ELASTOMER

The reason for these is much the same as “abrupt” stock rear linkages, i.e. to afford some sort of crude ride height control with a wide variance in load.

In road racing this causes a problem when braking and turning into the corner, as the suspension stroke has been linear (predictable) and compliant up to the last 30 - 35mm of stroke, but when the hydraulic bottoming device starts working there is a massive (and unwanted) increase in dampening force, leading to a semi hydraulic lock situation. Much of the load is still on the front tyre and when you are banked over you need as much mechanical grip as possible. The sudden increase in compression dampening force means the interlock with the pavement is lost and the tyre is overloaded.

The solution is to either reduce the effectiveness of these systems, or remove them altogether. This will require the rider to be vigilant on controlling the bottoming resistance with a balance of air gap, spring rate and dampening.

TYRE TEMPERATURES & GRIP

Correct suspension set up has a major effect on tyre temperature and wear patterns, but so also does any myriad of other factors such as abrasiveness of track, ambient air temperature and track temperature, etc.

For example, on a Cold day, a less abrasive track, you may only achieve temps of say 40 C.

But on a Hot day, track temp is say 40, the tyre temp may get to 80 – 100 C.

If rear tyre temp exceeds 85 C, raise tyre pressure 2 - 5psi.

Raise tyre pressure to reduce temp. Reduce tyre pressure to increase temp. Make sure to check tyre pressures when the tyres are on the warmers, but just as importantly, check pressures straight off the track too.

These comments are a guide only; tyre compounds and designs change constantly. For accurate info, talk to the tyre technicians at the race track.

 

Production

600cc

1000cc

Front

65 - 70 C

70 - 75 C

70 - 75 C

Rear

70 - 80 C

70 - 85 C

75 - 85 C

 

TYRE GRIP RELATED TO COMPRESSION DAMPING

Tyre grip is created when the tyre is pressed onto the track surface enough to interlock with the grain of the asphalt.

Not enough compression dampening or overly soft springing allows the tyre to move free and ride up on top of the pavement grain, commonly referred to in open wheeler racing as dry aquaplaning. With very high horsepower this means wheel spin will initiate earlier.

If the compression dampening is overly firm, grip will also decrease because too much downward force from the suspension will overheat the tyre or compress it too much and distort the carcass with unduly high load variations.

Don’t blame the tyre supplier for a problem that could be (and usually is) suspension set-up.

TYRE GRIP RELATED TO REBOUND DAMPING

Rebound is an event that occurs after the shock absorber has been compressed. Small track irregularities cause constant wheel movements (suspension movement) and rebound dampening controls this.

If the rebound dampening is too slow a loss of grip will occur that will be particularly noticeable on acceleration when exiting corners. The suspension remains pumped down (packing) and away from the compliant part of the stroke.

If the rebound dampening is too fast the wheel will spring away from the pavement at too great a rate causing the tyre to loose its interlock with the pavement. Fast rebound will have a particularly detrimental effect on braking, but also may allow the tyre to unload and spin on corner exit. The rider will often notice the rear feels “loose”.

Therefore the “sweet spot” has to be found by trial and error.

SUSPENSION STROKE

A road race bike should normally not use its full rear stroke. However on some circuits this is unavoidable, for example, Oran Park. If the suspension bottoms at a place where maximum grip is essential, the tyre cannot create it’s best traction because it also has to perform as a spring. This causes tearing of the tread from the resulting loss of adhesion.

Correction is achieved by an increase in spring rate or compression damping, sometimes both. More surface and tyre grip / faster lap times generally requires firmer settings (i.e. Phillip Island). Less grip / wet tracks require softer settings and a less aggressive steering angle.

FINAL THOUGHTS

DRY AQUAPLANING

Within given limits normal thinking is that if you want more grip you go to softer springs and/or dampening rates. This can be very far from the truth.

To illustrate:

The rear suspension unit consisting of a spring and a damper tries to counterbalance the effect of chain torque.

The combination must be firm enough to keep the wheel “pushed” ONTO THE ROAD SURFACE but also be compliant enough to absorb surface irregularities. (1)

Under acceleration, torque imparted through the top run of the chain tries to pull the wheel/tyre off the road. The more torque applied the greater the problem. (2)

READ THIS BEFORE YOU REFIT YOUR FORK & SHOCK

FRONT SUSPENSION

Triple clamps: Wipe the clamps out with a solvent, they must be clean and oil free. Use a “scotchbrite” pad if you need to remove any hard deposits. Feel the steering head bearings while you are at it do they move freely?

Axle: Check the axle for any nicks or burrs. NEVER HIT YOUR AXLE WITH ANYTHING HARDER THAN BRASS OR PLASTIC.

If your axle cannot centre in the axle foot, you will have a harsh feeling fork that you cannot remedy with clicker adjustment.

Install the forks and torque the triple clamps to manufacturer’s specification. Over tightening will cause binding in the upper tubes.

Set the fork projection through the top clamps to the stock position. If you have a projection preference and have not changed fork settings, set it to your previous figure.

Lubricate the axle with thin oil or WD40, run it through the feet and wheel bearings to ensure it is smooth. Install the wheel and the axle, but leave the pinch bolts loose.

After all the other assembly work is done, drop the bike off the stand, hold the front brake and “pump” the forks several times, to centre the axle and the fork legs. Tighten the pinch bolts while the bike is sitting on the ground. THIS STEP IS CRITICAL.

Look through the tuning notes and go ride.

TEKNIK SUSPENSION SETTINGS

Date:

Event:

Rider:

Bike:

 

Session

1

2

3

4

5

6

Track Temp

 

 

 

 

 

 

 

 

Bike

Front Tyre PSI

 

 

 

 

 

 

Rear Tyre PSI

 

 

 

 

 

 

Gearing

 

 

 

 

 

 

Wheelbase

 

 

 

 

 

 

Fastest Time

 

 

 

 

 

 

 

Front

Offset

 

 

 

 

 

 

Angle

 

 

 

 

 

 

Fork Type & #

 

 

 

 

 

 

HYD SPEC

 

 

 

 

 

 

Fork Height

 

 

 

 

 

 

Compression

 

 

 

 

 

 

Rebound

 

 

 

 

 

 

Spring Rate

 

 

 

 

 

 

Preload (mm)

 

 

 

 

 

 

Oil Level (mm)

 

 

 

 

 

 

Top Out Spring

 

 

 

 

 

 

 

Rear

Shock Type & #

 

 

 

 

 

 

Link

 

 

 

 

 

 

HYD SPEC

 

 

 

 

 

 

Compression

(LS, HS)

 

 

 

 

 

 

Rebound

 

 

 

 

 

 

Spring Rate

 

 

 

 

 

 

Preload (mm)

 

 

 

 

 

 

Top Out Spring

 

 

 

 

 

 

Shock Length

 

 

 

 

 

 

Swing Arm

Length

 

 

 

 

 

 

 

Offroad Bike Setup Guide

Our detailed Suspension Setup Guides help you get the most out of your Offroad bike, whether modified or stock.

Click to download original article or scroll down to the bottom.


GET THE MOST OUT OF YOUR OFFROAD BIKE WITH TEKNIK'S SUSPENSION SETUP GUIDE

ABOUT TEKNIK

Teknik Motorsport is a manufacturer and importer of motorcycle suspension products. We also have a workshop dedicated to developing and testing new products. Teknik is a family owned Australian company that is enthusiastic about motorcycling and is staffed by people who are passionate motorcyclists, and our products are manufactured in Australia wherever possible.

Teknik has been operating since 2001. We have been involved with Enduro legend Geoff Ballard, and the Ballards Yamaha Offroad team from 2001 and Lyndon Heffernan’s Academy Of Off-Road Riding since 2003. We have also built the suspension for the GHR Honda Off Road Team, in Enduro, off road and the Australian Safari, culminating with an outright win in the 2004 Safari.

In 2006 we ran two Kawasaki KX250F’s in our own MX Nationals Pro Lite MX team in conjunction with ADB magazine. A solid success, and team rider Mike Phillips has since gone on to much higher success.

For 2007/2008 we went road racing, attending every round of the ARRC, supporting a number of privateer riders in the Supersport class, and we performed major setup and development work for Craig McMartin on the 1098 and 1198 Ducati in Pro Twins. How’d he go? Two more CHAMPIONSHIPS! Lap records at every track, and nearly 2 seconds off his PB around his home track of Eastern Creek. Thats a win for Teknik and a win for you as all our development work from the track goes into your suspension.

All our parts and kits have been extensively tested in the field by both our own race team and riders we support.

INTRODUCTION

Today’s motorcycles are very advanced. Gone are the days of the owner having to finish the manufacturing. However, they are not perfect, they never can be. The nice folks who build your bike don’t know you. They don’t know if you weigh 60 kilos or 120 kilos. They don’t know whether you carry a bunch of gear. They don’t know if you ride SX, or natural terrain MX, or enduros.

Getting your suspension dialled in for your riding style is one of your first priorities when you take your new bike out on the track. However, it is an on-going process, and what worked today might not suit the next track conditions you encounter next week. Therefore, you have to take on the role of test rider yourself and learn to identify problem areas. Never stop testing and thinkingabout what your bike is doing. Read your owner’s manual too, it’s full of good stuff.

This booklet is full of practical information that can help people with both revalved or standard suspension, and has been compiled from archival material, conversations with race engineers, input from Suspension Tech NZ and our own ongoing experience working with top riders throughout Australia.

The figures we have come up with have generally worked very well but individual riders may get better results with alternative personalized settings. Our experience and personal education is ongoing and we hope these notes will assist in your set up, speed and safety. We will continue to offer our on track service at selected meetings and continue to develop our settings to the benefit of our clients.

When using this manual, it is intended that you start at the clickers section and work your way through. It is of little use making suspension and geometry adjustments when you have no idea of the basics: where your clickers are, ride height, springs rate, shock length. Remove the set-up sheet at the back of this manual and photocopy it. Keep the notes as a record for each track, and to give you direction when reviewing settings. If you don’t keep records, you will chase your tail all weekend.

To get started, I’ve included a quote from Ross Maeda of Enzoracing in California. Ross has a way of making complex systems seem simple…

“To understand how to start adjusting your suspension, you have to understand the basic components. Both the forks and shock have two key elements: the spring and dampening.

The spring is load or position-sensitive, which basically means it’s job is to hold the rider’s weight.

The dampening -- which is what the clickers control -- is a speed-sensitive element.

The spring is really just a dumb piece of metal that’s bending. It’s like a trampoline, if you stand on a trampoline, it holds you up; but if you jump on it, it goes down a lot deeper and throws up equally as high. If you just had a spring on a motorcycle -- and no dampening -- it would be like a car going down the freeway without shocks; it would bounce up and down for miles.

Adding dampening to the suspension is like putting that trampoline in water. It will still support your weight, but you don’t get the springy, bouncing effect.”

CLICKERS

Note: All clicker settings are referred to from the fully hard (clockwise) position.

Often we call a client on Monday after a race to see how they went. Occasionally we’re met with the response “it was too soft” or “it was to stiff”. Our next question is always “What clicker position did you start out at and where did you end up?

Did your adjustments help?” Sometimes the answer is:

“I DIDN’T TOUCH THEM, I LEFT THEM RIGHT WHERE YOU PUT THEM.”

Anyone who knows a suspension tuner will realise how much this drives them nuts. Find your suspension’s adjusters (commonly called clickers), and adjust them yourself. One adjustment at a time so you know what it is doing. Keep a note of where you started form, so if you get lost you can go back.

Adjusters are like a tap, closing off the tap to restrict the flow of oil and produce a firmer dampening character. When we turn the adjuster we are not adjusting the valving! We are simply changing the quantity of oil that bleeds past the valving. If you have the wrong valving setting for your application, you will not get an optimum set-up by just turning clickers, however you can improve the motorcycle and make it “the best it can be”. Likewise, even with a perfect shock specification, poor clicker settings will ruin the whole farm.

Turn the adjusters clockwise, counting the clicks or turns. Be gentle; don’t keep turning the screw or knob once it stops. Turn the adjusters back out to the original position. Write the number of clicks or turns down on the set-up sheet.

If in doubt, 10C (compression) and 10R (rebound) is a good place to start for forks with over 20 clicks total adjustment. 1 ½ turns for those forks with no clicks. Units with less total clicks, use a midway position.

For Shocks, again check they are in the suggested positions, and if in doubt, 1 turn out HSC,10 LSC, 10 R are good places to start for most dampers.

BASIC GEOMETRY

This can be broken down into sections.

  • Fork travel / length, usually left standard.
  • Fork height, the position of the fork in the triple clamps. This can be measured in lines above the top triple clamps. I personally prefer to measure length of fork between the bottom of the lower triple clamp and the end of the fork tube. This eliminates the question of do we measure from the front of back of the clamps and gets you used to making small changes, as one line on the clamps will often be 3mm
  • Triple clamp offset and rake, again usually left standard.
  • Rear shock length, including any raising spacers. A tremel bar is perfect for this. Measure the shock out of the bike with a spring on it to compress the internal top out spring
  • Linkage adjustments (or different length pull rods)
  • Swingarm length.
  • Tyre height if you use different profiles.

Forks:

  • Compression (C): For Closed Cartridge forks; Clicker is at the top of the fork. For Open Cartridge forks; Adjuster is at the bottom of the fork, sometimes covered by a rubber plug.
  • Rebound (R): For Closed Cartridge forks; Flat blade screw at the base of the fork. For Open Cartridge forks; screw is at the top of the fork.

Shock:

  • Low Speed Compression (LSC): Flat blade screwdriver fitting at the top of the shock.
  • High Speed Compression (HSC): Large hex nut at the top of the shock (it moves independently of the low speed). Some brands have clicks, others you need to count turns
  • Rebound (R): Flat blade screwdriver fitting at the bottom of the shock

SAG

Before you start making adjustments it’s best to know where you are starting from. First job is to check the suspension sag settings. This will allow you to check if you have the right springs and get used to making some adjustments. The “average” target weight for a full size motorcycle is a 75kg rider. Therefore, if that is how much you weigh, and if you have a MX or current technology enduro bike, chances are the spring rates will at least be close for you. Of course, you will need to check and adjust your sag to be sure.

There are however some exceptions. If you ride in sand or mud a lot, you might want to run heavier springs. Pro class riders on four strokes will also go for stiffer rates, as will x-treme jumpers. Often, OEM springs will lose some free length over time, so if you feel the motorcycle is not handling how it did, recheck the sag.

To start, raise the bike on a stand so both front and rear wheels are off the ground, and wind the clickers all the way to full soft so they don’t interfere with the results.

Measure from the rear axle to any fixed point on the rear side cover or muffler. You might find it easier to make a mark with a felt tipped pen at a convenient number.

We’ll use 500mm as an example. You need to be quite accurate as a few mm will make a difference.

Measure the forks using the same process.

Put the machine back down on the ground and have the rider sit in their normal riding position.

Wearing riding gear is preferable but you can estimate the measurement by adding 5mm to account for the extra weight.

In our example the measurement is now 380mm, therefore we have a ride height, or rider sag, of 120mm (500 minus 380).

Lastly we measure the height with no rider to determine how much the machine sags under it’s own weight.

Our measurement is 480mm, so we have 20mm “static” sag.

If the machine we are measuring is a motocross bike and we require 100mm rider sag, we would need to wind a lot more preload onto the rear spring to achieve this. However as we only have 20mm static sag if we wind more preload on we will have no static sag, so we need to go to a stiffer spring. See the following tables for a general guideline.

  • If you have too much rider sag or too little, increase or decrease the amount of spring preload to get it closer.
  • Then if static sag is correct, Rider sag less than minimum – spring is too firm (or if rider correct & static more than max)
  • Static sag correct, rider sag more than max – spring is too soft (or if rider correct & static less than min)

FORK SAG

 

125 / 250 / 450

MX & Enduro

with 300+mm

suspension travel

80 / 85cc

Mini MX

50 / 65cc

Mini MX

KTM PDS

XR 250 / 400

/ 600 / 650,

KLX 250 / 300,

DR650

DRZ / KLX 400

Static Sag

30 +/- 10 mm

15 +/- 5 mm

15 +/- 5 mm

30 +/- 10 mm

30 +/- 10 mm

30 +/- 10 mm

Rider Sag

50 +/- 10 mm

40 +/- 5 mm

30 +/- 5 mm

50 +/- 10 mm

50 +/- 10 mm

50 +/- 10 mm

 

Note:

  1. Soft springs require more preload, hard springs less preload. Final selection is not only dependent on final figures but also personal preference. Very often a firmer spring rate will be more complaint in the first part of the stroke because it requires a lot less preload.
  2. Excessive pre-load on overly soft front fork springs will cause harsh feel and poor mechanical grip.
  3. “Normal” preload range is 3 - 14mm. Lighter springs require more preload, heavier springs require less.
  4. For a given rider there will usually be 2 or perhaps 3 spring rates that could be used, depending on the track and personal preference.
  5. To minimize front fork stiction (commonly used term to describe the level of force needed to overcome friction) it is very important that axle pinch clamps are only tightened after the forks have been compressed several times to ‘neutralize’ their position. Failure to do so can sometimes result in substantial stiction.

REAR SAG

- Equates to normally 1/3rd of full stroke as a starting point

 

125 / 250 / 450

MX & Enduro

with 300+mm

suspension travel

80 / 85cc

Mini MX

50 / 65cc

Mini MX

KTM PDS

XR 250 / 400

/ 600 / 650,

KLX 250 / 300,

DR650

DRZ / KLX 400

Static Sag

30 +/- 8 mm

10 +/- 3 mm

10 +/- 5 mm

38 +/- 3 mm

25 +/- 5 mm

25 +/- 5 mm

Rider Sag

100 +8/- 3 mm

85 +/- 3 mm

65 +/- 5 mm

110 +8/-5 mm

85 +/- 3 mm

85 +/- 3 mm

 

Note:

  1. The above settings are guidelines only, and some riders may have better ‘feel’ and speed with alternative settings.
  2. The PDS system is very sensitive to rear height changes. We suggest 105mm ride height to begin with, however 90 - 110mm is a practical working range
  3. Machines with less suspension travel like the Honda XR use 85mm rear ride height.
  4. KTM 85’s work best with near 100mm of rider sag.
  5. Soft springs require more preload, hard springs less preload. Final selection is not only dependent on final figures but also personal preference. Very often a firmer spring rate will be more complaint in the first part of the stroke because it requires a lot less preload.
  6. As with the forks there are usually 3 spring rates that can be used and still be “correct”. We suggest that you measure your springs off the shock and then measure the installed length so you know the preload in mm. For example, if you are using a 90Nm shock spring but wish to fit a 95Nm spring, and you know that you are using 13mm of preload on the 90Nm spring then a reduction of 1mm in spring preload to 12mm will get you a similar starting point to maintain geometry but the 95Nm will “ramp up” more as you use more travel.

FORK TUNING

SETTING THE COMPRESSION

  1. The forks should react to all track variations. If the forks seem harsh on small bumps or holes, soften the compression (turn clicker out). If they aren’t, stiffen the compression (turn clicker in) until they do feel harsh and then turn back a click or two.
  2. Now find the rough part of the track again. The forks should bottom over the worst obstacle. If harsh bottoming occurs, add oil in 5mm increments.

SETTING THE REBOUND

The rebound damping is responsible for the stability and the cornering characteristics of the motorcycle.

  1. Find a short sweeper. When the forks compress for the turn, the speed at which the forks return is the energy that pushes your front wheel into the ground. If the forks rebound too quickly, the energy will be used up and the bike will drift wide, or wash. If the rebound is too slow, the bike will tuck under and turn too soon to the inside. Find the appropriate balance for each track.
  2. With the bike turning well, the wheel should return to the ground quickly yet not deflect off berms or bounce off jumps.

FORK OIL LEVEL

Note: Oil height is measured from the top of the outer leg, with the top nut off, the fork fully compressed and no preload washer or spring installed.

OIL LEVEL RAISED: Forks firmer towards the end of the stroke

OIL LEVEL LOWERED: Forks softer towards the end of the stroke

There are 2 forms of spring in every fork, the wire coil springs, and the air trapped in the fork above the oil. Both springs are sensitive to their position in the stroke, but not to speed (the dampening character is sensitive to the speed the fork compresses but not to position).

If you are using linear or straight wound springs, they will provide a linear progression in stiffness as the fork compresses. The air spring or air gap character is not linear; as you can see from the graph below, it has little influence in the first 1/2 of the stroke, but has a dramatic influence in the last 1/3. Too low and the fork will bottom too easily, too high and the fork will loose it’s compliance in the last part of the stroke.

Twin chamber forks are also sensitive to oil height in a different way, the spring perch causes a secondary dampening effect when it plunges into the oil, raising the oil height beings this secondary effect in sooner.

FORK TROUBLESHOOTING

FRONT END FALLS INTO THE CURVES (OVERSTEERING) ESPECIALLY IN SAND

Steep front fork angle. Front end too low in comparison to rear end.

  1. Increase the front fork compression damping.
  2. Change to harder springs.
  3. Lower fork leg approximately 5 mm in the triple clamp.

FRONT END UNSTABLE DURING DECELERATION

Front fork angle too steep during braking. Front end too low or rear end to high.

  1. Increase the oil level in the front fork.
  2. Change to harder fork springs.
  3. Increase the fork compression damping.

FORK TRAVEL IS NOT USED TO ITS FULL CAPACITY, HARSH FEELING, UNSATISFACTORY FRONT WHEEL GRIP IN BUMPY TURNS

Suspension is too hard.

  1. Decrease the fork compression damping.
  2. Change to softer springs.

SUSPENSION BOTTOMING, BUT CAN HANDLE SMALLER BUMPS

Damping force not progressive enough.

  1. Increase oil level.

CAN HANDLE SMALLER BUMPS BUT IS TOO HARD DURING THE LAST PART OF TRAVEL

Damping force is too progressive.

  1. Decrease oil level.

FRONT END FEELS LOW, INITIALLY FEELS SOFT, BUT IS NOT BOTTOMING

Too much spring preload, or too much compression damping.

  1. Increase the oil level or change to softer springs.
  2. Decrease the compression damping.
  3. Decrease the spring preload.
  4. Clean the oil seals and scrapers.

CAN HANDLE THE FIRST IN A SERIES OF BUMPS BUT FEELS HARD AFTER A FEW MORE BUMPS, FRONT GRIP INSUFFICIENT IN ROUGH & BUMPY TURNS

Too much rebound damping.

  1. Decrease the rebound damping.

FRONT END REBOUND TOO FAST AFTER A BUMP, FRONT WHEEL GRIP INSUFFICIENT IN BUMPY TURNS

Not enough rebound damping, or too much spring preload.

  1. Increase the rebound damping.
  2. Decease the spring preload.

HEADSHAKE

Too much or too little weight on the front wheel, springs or dampening incorrect.

  1. Be sure the fork is not abnormally soft or hard. If it is, go through the steps above.
  2. Reduce the rebound dampening.
  3. Check the fork springs are correct for your weight.
  4. Check the steering head bearings, be sure there is a slight amount of preload on the bearings and they are well greased.

BIKE DOES NOT WANT TO TURN

Not enough weight on the front wheel

  1. Try increasing the rear shock preload. Don’t go under 15mm of static sag.
  2. Slide the forks up in the triple clamps 5mm.
  3. If the rear is not too stiff try increasing the rear compression dampening (low speed if you have a 2-way compression adjuster).
  4. If you have no problem with headshake, try increasing the forks rebound dampening two clicks at a time.
  5. If you have no problem with the fork bottoming, try decreasing the forks compression dampening 2 clicks at a time.
  6. Are the forks centred in the axle, has this problem just occurred after removing and refitting the forks?
  7. If possible, reduce the amount of fork spring preload, or go to a softer spring as a last resort.

SHOCK TUNING

SETTING THE COMPRESSION

  1. Find a corner with acceleration bumps on the exit. The rear of the motorcycle should follow the ground. If the rear end “breaks up”, soften the compression. (turn clicker out) (If this fails, soften the rebound two clicks).
  2. Find some rough sections, a large jump and a couple of “G-Outs”. The shock should bottom on the roughest section but it should not be a slamming sensation. Add compression to fight bottoming (turn clicker in). But avoid going to far as small bump ride will be sacrificed in the trade. Remember the adjusters have a primary effect on the low speed, so even a large change in setting may only affect bottoming resistance slightly. Bottoming your suspension is not necessarily a bad thing. You should strive to bottom off the biggest bottoming load obstacle on the track. If you don’t, you’re not getting maximum plushness from your suspension.

SETTING THE REBOUND

  1. Find a relatively fast straight with braking bumps leading into the entrance of a corner. Reduce (turn clicker out) the rebound damping until the rear end begins to hop or feel loose. Finally, increase (turn clicker in) the rebound damping until the sensation goes away.
  2. Find a jump that tends to launch the motorcycle out. The rear end should absorb and then smoothly lift the motorcycle into the air. If the rear end bounces up, add rebound (turn clicker in).
  3. Find some large whoops. The motorcycle should track straight through the whoops with the rear wheel extending to the ground before the next impact. If it does not perform as described as above, it is packing and the rebound damping should be reduced! (turn clicker out). (Please note the guide for sand set-up, as these rules don’t apply for sand).

TOO MUCH LOW SPEED REBOUND DAMPING

Rear end tends to wash out or slide-out on hard packed sweeper turns with small bumps especially off-camber “washboard” sections does not develop good braking power.

Poor rear wheel hook up when accelerating over series of small bumps or “washboard” sections.

In general, rear end seems to be well controlled in the situations it is not oscillating up and down too much but it just doesn’t seem to develop good traction.

Note: All these problems arise because the excess damping keeps the rear wheel from extending fast enough to follow the low spots between the small bumps the result is poor traction.

TOO LITTLE LOW SPEED REBOUND DAMPING

The symptoms here are similar to the left; a tendency to slide out on “washboard” turns and poor braking over washboard sections, but the critical difference in this case is that the back of the bike is bouncing up and down too much.

Not enough rebound damping causes too much kicking up, especially noticeable when braking on downhill sections with small bumps or over a washboard surface.

SHOCK TROUBLESHOOTING

REAR END DOES NOT HOOK UP

  1. Re-check the rear suspension sag. Not enough preload can cause this.
  2. Reduce the rear’s rebound dampening, this allows the rear wheel to get back on the ground faster and increase traction.
  3. Check the rear axle position, if it has been moved all the way rearward, then shorten or replace the chain.
  4. Re-check your HSC adjuster if the problem is more predominant on rocks and roots. Decrease (wind out) the HSC adjuster.

CAN’T HANDLE THE WHOOPS

  1. Try increasing the rear compression dampening, especially high speed if you have it.
  2. Increase the rebound dampening but not so much that it “packs” in repeated bumps.

EXCESSIVE REAR END KICK UNDER POWER

  1. Check for packing, which is identified by kick to side in hard to loam conditions. If you observe packing, soften rebound (turn clicker out). This cannot be avoided if you brake improperly and lock the rear wheel up and/or pull in the clutch, on the entrance to corners.
  2. Often rear end kicking under power is bottoming; try going stiffer on compression or increasing rear spring preload.

REAR END BOTTOMS OUT

  1. Increase compression dampening.
  2. Increase spring preload but don’t go more than 5mm under the recommended rider sag for your model.
  3. Decrease rebound dampening.

SUSPENSION SUMMARY

GOING TO DIFFERENT TRACKS

Keep a record of the different settings you used at each track. That way you can start at a point that worked well the previous times. Remove the set-up sheet at the back of this manual and photocopy it.

The following are some tips that will help you set up for particular types of terrain.

Hard Pack to intermediate:

Set the compression softer (turn clicker out), both front and rear to help get maximum wheel contact and plushness.

Sand tracks: (Non-square edged bumps)

More low speed compression and rebound are necessary. Start by adding 1 - 2 clicks (turn clicker in) of rebound and as the track gets rough, add 1 - 4 clicks (turn clicker in) of compression. Harshness is a result of packing in forks. Remember to add compression (turn clicker in) to help keep the front end from packing. The rear suspension will exhibit packing by swapping. To eliminate swapping, begin adding compression (turn clicker in) until the bike tracks straight, and then add rebound (turn clicker in) to keep the rear following the terrain of each whoop. Don’t be concerned if your clickers are nearly maxed out in sand conditions. Unless of course you have had your bike revalved for sand.

Supercross: (G-load, curb hits)

G-loads produce slow piston speeds. This means that less dampening is produced by the shock and forks in a situation that causes more of a bottoming load. To set your bike up for Supercross, adjust the compression stiffer (turn clicker in) on the suspension (2 - 6 clicks), and in some circumstances raise oil level and/or change to stiffer springs.

DAMPING SYSTEMS SUMMARY

Dampening Adjustment

Best places on track for testing

Perfect When

Low Speed

Rebound Dampening

  • Small bumps
  • Sweeper turns over washboard sections
  • Off-camber washboard turns
  • Braking on washboard surfaces

Heavy enough to prevent rear end bouncing or oscillation yet light enough to allow rear wheel to extend. Fast enough to maintain good contact with ground. Rear end tracks well on washboard sweeps and off-camber washboard turns; brakes well on washboard.

High Speed

Rebound Dampening

  • Series of medium or large rolling type bumps on high speed sections
  • Fast downhill sections with deep rolling bumps

Heavy enough to prevent rear end kicking up, yet light enough to prevent “packing down” on series of bumps.

Low Speed

Compression Dampening

  • Small bumps and medium bumps
  • Deep rolling sand whoops
  • Washboard sections
  • Deep smooth gullies

Heavy enough to prevent bottoming out on bumps or rising sand whoops at the bottom of deep smooth gullies, yet light enough to allow shock to stroke smoothly on small bumps and avoid skipping when braking on washboard surfaces.

High Speed

Compression Dampening

  • Big square edges bumps in fast sections
  • Big jumps

Heavy enough to prevent excess bottoming out off jumps or over large square edged bumps yet light enough to stroke deeply to absorb these bumps without harshness or rigidity.

 

WASHING & BIKE CARE

Wash your bike after every ride so you can inspect the fork chrome tubes for knicks or scratches that will lead to seal failure. For upside down forks keep the chrome tubes free of dry mud that the dust scrapers will not be able to dislodge. After the wash, a light coating of water dispersing oil (WD-40) will keep the seals and wipers lubricated. To maintain optimum performance, lever the fork dust scraper down and clean the dust build up from around the seal and wiper. Then apply general purpose grease lightly, and refit the wiper.

For the shock, lift the bump stop up periodically with a screwdriver and wash under the bump stop. This is a common area where shock shaft corrosion starts. If the flap that protects the shock becomes damaged, replace it; or the roost off the rear wheel will damage the shaft.

SUSPENSION REFITTING

READ THIS BEFORE YOU REFIT YOUR FORK & SHOCK

FRONT SUSPENSION

Triple clamps: Wipe the clamps out with a solvent, they must be clean and oil free. Use a “scotchbrite” pad if you need to remove any hard deposits. Feel the steering head bearings while you are at it do they move freely?

Axle: Check the axle for any nicks or burrs. NEVER HIT YOUR AXLE WITH ANYTHING HARDER THAN BRASS OR PLASTIC. If your axle cannot centre in the axle foot, you will have a harsh feeling fork that you cannot remedy with clicker adjustment.

Install the forks and torque the triple clamps to manufacturer’s specification. Over tightening will cause binding in the upper tubes.

Set the fork projection through the top clamps to the stock position. If you have a projection preference and have not changed fork settings, set it to your previous figure.

Lubricate the axle with thin oil or WD40, run it through the feet and wheel bearings to ensure it is smooth. Install the wheel and the axle, but leave the pinch bolts loose.

After all the other assembly work is done, drop the bike off the stand, hold the front brake and “pump” the forks several times, to centre the axle and the fork legs. Tighten the pinch bolts while the bike is sitting on the ground. THIS STEP IS CRITICAL.

Look through the tuning notes and go ride.

After riding, raise the front wheel off the ground and release the air that builds up in the forks.

REAR SUSPENSION

Start tuning at standard ride height

Move the swing arm up and down to check for binding in the linkages.

Fit the shock, and torque the bolts to specifications.

Again, look at the tuning notes before riding.

On your first ride, start riding carefully. If you have had a major change to your suspension settings your bike will react differently on the track and you may crash as a result.

TEKNIK SUSPENSION SETTINGS

Date:

Event:

Rider:

Bike:

 

Session

1

2

3

4

5

6

Track Temp

 

 

 

 

 

 

 

Bike

Front Tyre PSI

 

 

 

 

 

 

Rear Tyre PSI

 

 

 

 

 

 

Gearing

 

 

 

 

 

 

Wheelbase

 

 

 

 

 

 

Fastest Time

 

 

 

 

 

 

 

 

Front

Offset

 

 

 

 

 

 

Angle

 

 

 

 

 

 

Fork Type & #

 

 

 

 

 

 

HYD SPEC

 

 

 

 

 

 

Fork Height

 

 

 

 

 

 

Compression

 

 

 

 

 

 

Rebound

 

 

 

 

 

 

Spring Rate

 

 

 

 

 

 

Preload (mm)

 

 

 

 

 

 

Oil Level (mm)

 

 

 

 

 

 

Top Out Spring

 

 

 

 

 

 

 

Rear

Shock Type & #

 

 

 

 

 

 

Link

 

 

 

 

 

 

HYD SPEC

 

 

 

 

 

 

Compression

(LS, HS)

 

 

 

 

 

 

Rebound

 

 

 

 

 

 

Spring Rate

 

 

 

 

 

 

Preload (mm)

 

 

 

 

 

 

Top Out Spring

 

 

 

 

 

 

Shock Length

 

 

 

 

 

 

Swing Arm

Length

 

 

 

 

 

 

 

 

Using Your Clickers

Ever adjusted your suspension? Scared you'll stuff it up if you make any changes?

If you've never touched your clickers, then your suspension could be better than it is, for free. Understanding the basics of suspension and adjusting them using the built-in (on most bikes) adjustable suspension means you could be riding faster, enjoying your riding more, and avoiding those aches & pains you get after a blast.
Have a read of our basics guide, and tinker away!
Courtesy of our good friends at Transmoto Magazine.
 

Camshaft Degreeing Instructions

Cam timing is essential to good power.

Click to download original article or scroll down to the bottom.


AN EASY GUIDE TO DIY CAMSHAFT DEGREEING

The purpose of degreeing a camshaft is to ensure that it is phased correctly with the crankshaft. Some of the factors that may cause improper positioning are:

  1. Cam or crank gear marked incorrectly
  2. Improperly machined crank or cam keyways and splines
  3. Accumulation of machine tolerances (head and or barrel machining)

Equipment needed to properly “degree” in a camshaft

Available from most performance auto outlets and machine shop suppliers. We can supply a kit from Hotcams.

  1. Degree wheel
  2. Rigid pointer that can be attached to the engine cases. (Note: refer to your specific cam card to ensure your dial indicator has enough range to measure maximum lift.)
  3. A base that the dial indicator can attach to the rocker cover region
  4. A top dead centre stop or a dial indicator that will reach the piston crown with the head on.
  5. A means to attach the degree wheel to the crankshaft

The intake centreline method

There are several accepted ways to degree a camshaft. We feel that the exhaust centreline is the easiest and most accurate. This method of cam degreeing is very practical and indifferent to lobe design characteristics. It simply involves positioning the centre, or point of maximum lift, of the exhaust lobe with Top Dead Centre (TDC). The exhaust centreline method still requires accuracy to be correct, but is somewhat more forgiving. Once you have degree’d a camshaft using this method, you will be surprised at its ease. We do recommend using the exhaust cam over the intake as the exhaust timing is more critical (this only applies to 4 lobe cams like XR RFVC engines, twin cam engines need both the inlets and exhausts checked). Position the dial indicator onto the valve spring retainer, or bucket. This makes the process as accurate as possible in relation to what actually goes on inside the engine.

Camshaft degreeing in 12 steps

Step 1

The camshaft and timing tensioner have been installed. Make sure the timing marks on both the flywheel and cam gear are aligned as per the workshop manual

Step 2

For example, we have our cam and it suggests we install the cam on 105 degree exhaust centrelines. Adjust the tappets to the clearances recommended by the cam manufacturer.

Step 3

Attach the pointer to the cases. Many people will make a pointer out of some sort of ridgid yet manageable wire. A coat hanger works well

Step 4

Attach the degree wheel to the crank snout. You may need to space the wheel out to clear the cases, use the flywheel bolt. Rotate the engine from the other end of the crank or you could move the degree wheel if you turn the engine by the flywheel bolt.

Never rotate the engine with the kick-starter while checking clearances. Use a long lever to rotate the engine. Remember the longer the lever, the smoother you will be able to rotate the engine thus more accuracy.

Step 5

Before installing the piston stop, rotate the crankshaft to TDC with both exhaust and intake valves closed. This can be a rough guess but will save you from a mistake later. Adjust your pointer to zero or TDC on the degree whee.

Step 6

Turn the crankshaft opposite the engine rotation approximately 20 degrees, this will lower the piston enough to allow the TDC stop to be installed in the sparkplug hole. Screw in the piston stop until it touches the piston continue to turn the engine the same direction until the piston comes back up and touches the piston stop, mark the degree wheel with a pencil on the number the pointer is on. Turn the engine in the other direction, same as engine rotation until the piston comes back up and touches the piston stop; make a mark on the number the pointer is on. To calculate TDC add both of the numbers together and divide by two. 18 + 14 = 32 / 2 = 16. TDC is therefore at 16 degrees, adjust the pointer to 16 degrees and you have TDC.

Step 7

Check step 6 again! This step by step is critical to proper cam alignment.

Step 8

Attach the dial indicator to the dial indicator mount. Position the indicator mount so the tip will contact the retainer of the exhaust valve. It is important that the indicator plunger be parallel to the valve stem.

Step 9

Rotate the engine in the normal direction of engine rotation until you reach maximum lift. The dial indicator will change direction at the point of maximum lift. At this point set the dial indicator at zero.

Step 10

Turn the engine backwards until the indicator reads 0.100 thou turn the engine back in the normal direction of rotation until the dial indicator reads 0.010 before maximum lift record the degree wheel reading.

Step 11

Continue to rotate the engine over its normal direction of rotation until the indicator goes past zero to 0.010 on the closing side of maximum lift. Again record the degree wheel reading.

Step 12

Add the two numbers together and divide by two that number will be the location of maximum lift on the exhaust lobe in relation to the crank and piston. This is the exhaust centre line.

For example the first degree wheel reading was 96 degrees the second reading was 116 degrees, these two numbers (96 + 116) and added together will be 212. 212 / 2 will = 106 you actual exhaust centre line is 106. Refer back to your cam spec card and we see that the recommended intake centreline for you camshaft is 106 degrees, everything is where it should be.

In the event your camshaft did not degree as per the cam-card it will be necessary to either advance i.e. (move the cam ahead) or retard (move the cam back) the cam to meet exhaust centreline.

To allow cam adjustment you will need to file the cam bolt holes this can be done with a chainsaw blade sharpening file. After setting the exhaust centreline locktite and torque the cam securing bolts to manufacturing specifications.

Keep in mind that to advance the cam you must lower the intake centreline. For example if our cam has a lobe separation of 110 degrees the cam is “straight up” when the intake centreline is 110 degrees. Moving the centreline to 106 degrees advances the cam 4 degrees. If we change the centreline to 112 degrees, this would be 2 degrees retarded.

 

2006 Kawasaki KX Suspension Chart

This guide gives you the numbers for optimum performance, courtesy of Team Green USA.

2006 Team Green (USA) Recommended Suspension Setting Chart

FRONT FORKS

REAR SHOCK

Rider

Weight

Fork

Position

(height)*

Spring Rate

Oil Level /

Volume

Oil Weight

Reb Out

Comp

Out

Spring Rate

Preload/ SAG

Level

 

Reb Out

 

 

Comp Low Speed /

Pull Rods

 

Comp High Speed

Nitro Pressure

 

KX65A6F

 

 

 

 

 

 

 

 

 

 

 

 

 

25-30

30-34

34-39

15mm

10mm

Flush

0.26 Light

0.27 Stock

0.28 Heavy

130mm

130mm

125mm

10

10

10

2****

2****

3****

n/a

n/a

n/a

4.7

4.9

4.9

Light

Stock

Stock

70mm
70mm

70mm

2****

1.5****

1****

**STK

**STK

85.3mm

 

140psi

140psi

140psi

KX85A6F

 

 

 

 

 

 

 

 

 

 

 

 

 

Up to 34

34-45

45-52

52-57

Std

Std

Std

Std

0.27 Ex Light

0.28 Light

0.29 Stock

0.3 Heavy

90mm

90mm

90mm

80mm

5

5

5

5

n/a

n/a

n/a

n/a

8

8

8

8

4.4

4.6

4.8

5

Extra Light

Light

Stock

Heavy

80-85mm

80-85mm

80-85mm

80-85mm

9

9

8

8

1

1

1

2

 

150psi

150psi

150psi

150psi

KX85B6F

 

 

 

 

 

 

 

 

 

 

 

 

 

Up to 34

34-45

45-52

52-57

Std

Std

Std

Std

0.27 Ex Light

0.28 Light

0.29 Stock

0.3 Heavy

90mm

90mm

90mm

80mm

5

5

5

5

n/a

n/a

n/a

n/a

8

8

8

8

4.4

4.6

4.8

5

Ex Light

Light

Stock

Heavy

80-85mm

80-85mm

80-85mm

80-85mm

9

9

8

8

2

2

2

2-3

 

150psi

150psi

150psi

150psi

KX250R6F

 

 

 

 

 

 

 

 

 

 

 

 

 

59-68

68-77

77-86

7mm

7mm

7mm

4.3 Light

4.4 Stock

4.5 Heavy

310cc

310cc

310cc

5

5

5

14

14

12

6-10

6-10

6-10

5.1

5.3

54 N/mm

Light

Stock

Heavy

102-105mm

102-105mm

102-105mm

8

7

7

10-12

10-12

10-12

Full Soft

Full Soft

Full Soft

150psi

150psi

150psi

KX250T6F

 

 

 

 

 

 

 

 

 

 

 

 

 

57-64

64-72

72-82

82-88

5

5

5

5

4.2 Light

4.2 Light

4.4 Stock

4.5 Heavy

360cc

370cc

370cc

370cc

5

5

5

5

12

12

10

8

8-12

6-10

6-10

6-10

48 N/mm

50 N/mm

52 N/mm

54 N/mm

Extra Light

Light

Stock

Heavy

102-105mm

102-105mm

102-105mm

102-105mm

12

11

10

9

6-10

6-10

6-10

6-10

1.0-1.5

1.0-1.5

1.0-1.5

1.0-1.5

150psi

150psi

150psi

150psi

KX450D6F

 

 

 

 

 

 

 

 

 

 

 

 

 

59-68

68-77

77-87

5

5

5

4.5 Light

4.6 Stock

4.7 Heavy

Stock

Stock

Stock

5

5

5

12

10

8

6-12

6-12

6-12

50 N/mm

52 N/mm

54 N/mm

Extra Light

Light

Stock

102-105mm

102-105mm

102-105mm

8-9

8-9

7-8

6-8

6-8

6-8

1.0-1.25

1.0-1.25

1.0-1.25

150psi

150psi

150psi

 

 

*Fork Height is measured from top of fork tube to top of fork clamp.

**Stock 86.3mm pull rods on the 2002 KX65 can be exchanged for optional 85.3mm or 87.3mm to raise or lower the seat height by 4.5mm each.

****Refer to the 2006 KX65 owners manual for position information.

FOOTNOTES - Rebound and compression adjustments are the number of clicks out from full hard (all the way in). Front fork oil level is measured in millimeters (mm) or in cc for measured volume. Rear shock sag level is measured in millimeters (mm). All optional spring part numbers can be found at your local Kawasaki dealership.

SPECIAL NOTE - Team Green recommends that any suspension setting changes be done at normal riding temperatures. Team Green recommends that sag measuremnts be done when the shock is cold. Always test new settings before racing. *Team Green Specifications subject to change.

 

 

2009 ProLite Info Comparison

We took a hard look at the 250cc bikes from 2009, and figured out which mods help make them better.

2009 Pro Lite Spec Sheet

Our recommendations are for a 75KG rider racing motocross.

 

CRF250R

KX250F

RMZ250

YZ250F

KTM 250SXF

 

Standard

Recommended

Standard

Recommended

Standard

Recommended

Standard

Recommended

Standard

Recommended

Front tyre

Dunlop 742FA

B'stone M403

B'stone M403

B'stone M403

 

B'stone M403

B'stone M403

B'stone M403

B'stone M70

B'stone M403

Rear tyre

Dunlop 756

B'stone M404

B'stone M404

B'stone M404

 

B'stone M404

B'stone M404

B'stone M404

B'stone M50

B'stone M404

Gearing

13/51

 

13/48

 

12/48

13/52

13/51

 

13/48

 

Fork height

Flush

5mm

8mm

8mm

 

 

5mm

 

 

 

Comp clicks

12

12

6

10

10

14

9

 

12

22

Rebound clicks

12

12

12

12

14

14

10

 

20

12

Fork spring rate

0.46kg/mm

0.44kg/mm

0.45kg/mm

0.44kg/mm

0.44kg/mm

0.44kg/mm

0.46kg/mm

0.44kg/mm

0.45kg/mm

0.44kg/mm

oil capacity

360cc

350cc

360cc

360cc

360cc

360cc

350cc

360cc

360cc

360cc

Shock spring rate

5.3kg/mm

4.8kg/mm

5.1kg/mm

4.8kg/mm

5.4kg/mm

5.0kg/mm

5.3kg/mm

4.8kg/mm

69Nm

Progressive D

comp clicks

14

12

 

 

11

 

9

 

15

23

HSC clicks

3 turns

2

 

 

2 T

 

1.5T

 

 

 

rebound clicks

9

9

 

 

5

 

8

 

22

20

sag height suggested

100mm

100mm

100mm

100mm is critical

100mm

100mm

100mm

100mm

110mm

113-118mm

static sag suggested

35mm

35mm

100mm

35mm

35mm

35mm

35mm

35mm

35mm

35mm

Jetting

 

 

 

 

 

 

 

 

 

 

Fuel screw

1.5 turns

 

2 turns

2 turns

2 turns

2 turns

2 1/4

2 1/4

1.5

1.5

Pilot jet

42

40

40

42

42

42

45

45

40

42

Main jet

178

172

182

178

170

170

178

178

175

178

Needle

NMTU

NMTU

NHJT

NCYS

NLDT

NLDT

NFLR5

NFLR5

OBEKP

OBEKP

clip#

#3

#3

#4

#3

#4

#4

#4

#4

#4

#4

wire pump Y/N

 

No

 

Yes

 

Yes

 

No

 

Yes

Leak jet

70

65

55

60

45

55

70

60

50

50

Notes

New cylinder head for 09 with different porting and valve seats.

Rear spring losses free height quickly.

23.5mm offset triple clamps for 2009. Best results are with 22mm offset clamps. Rear spring rate selection and sag heights are crucial, 100mm sag must kept.

Rear shock stock setting does not have enough rebound dampening for many riders, same setting as 2008. Needs a pipe. Stock 12 tooth front sprocket wears chain guides.

42 Pilot can be used at altitude.

Convert engine to wet sump if clutch life is short. Needs a pipe.

20mm offset is standard on the 2 way adjustable clamps. Fork and shock settings are too stiff for most riders, hence the clicker settings.

 

 

 

 

Honda CRF1000L Africa Twin Suspension Modifications

Looking for some Honda CRF1000L Africa Twin suspension modifications? Here are our frequently asked questions and how we adjust the Africa Twin forks and shocks.

Click to download original article in Adventure Rider Magazine or scroll down to the bottom.
Courtesy of Adventure Rider Magazine.


Honda CRF1000L Mods

In issue #23 we rode a trio of Africa Twins and thought the stock suspension was good. Then we rode a couple where the suspension had been sorted and tuned by Nick Dole at Teknik Motorsport and we were amazed that what seemed a good stock set up could be improved so dramatically. Nick was happy to share what he’s learned about Honda’s dualsporter...

In the last 10 years, the DR650 was the king of the hill in terms of the amount of them we upgraded the suspension on. That’s changed in the last 6 months. We now do more Africa Twin than any other bike. It’s not because it’s a bad stock, it’s just the sheer sales volume, 400 bikes are rolling off dealers floors each year.  It’s selling well, lots of people love them stock, lots get modified. We do everything from changing springs, modifying OEM fork and shock internals, fitting Ohlins, Nitron and Andreani cartridges, to complete Ohlins forks. Ohlins shocks and now TFX shocks. There are a lot of companies making AT suspension components.

How does a typical Africa Twin phone call go? It’s varied. Remember a LOT of people buy this bike and love it stock. I get everything from “I read on the internet I should get it done” to “I bottom it so hard I may be in need of spinal fusion soon”. Clearly, we are dealing with a wide range of riders and uses.

If the caller is lost, just wants an improvement but doesn’t know why, asking what they use the bike for usually reveals why they are calling. Typical responses with my suggestions to no cost remedies are:

The forks are too soft and dive a lot.
Ok, have you adjusted the preload? Stock the fork has very little internal preload and you can make the fork sit a lot taller by winding 8-10mm (Turns) on the blue preload adjusters on the fork tops. I’s suggest you run the rebound adjusters on the fork caps at 1.0 turn out from full hard and the compression adjuster at the bottom 5 click out from full hard.

The shock gets hot and fades.
The AT has what I’d call a very active shock. I have heard your complaint before and done shock dyno tests at 30 to 120 degrees. The shock doesn’t fade any more than any other shock, it’s just that the level of damping the shock provides stock is very low, so any heat diminishes the damping and you quickly get out of “the window”, try running your rebound adjuster at 3 out from full hard and see if the problem is still there.

I have to run the shock preload at full hard all the time. I’m only 120kg, how could they have built a bike so soft?!?
(Suppressing laughter) The manufacturer has to target a weight range when they build a motorcycle, the stock rear spring isn’t suited to 120kg plus some gear. The shock’s damping targets aren’t meant for a stiffer spring so we are really looking at spring and damping changes.

So, what to do? Let's cover the OEM shock and fork because it’s the most popular to modify.

Honda CRF1000L Africa Twin Front Forks

Honda Africa Twin Fork

The stock fork is a Showa 45mm USD unit. It’s closer to a late 80’s Honda MX bike than a 2018 CRF450R but that still puts it above or at least on par with its sales rivals. The stock springs are 0.54-0.56kg/mm progressive. That’s not a bad stock spring to have. A few shock dyno runs and some riding unearth who Honda designed the bike for. It’s made to be comfortable and do everything. It’s not supposed to be a CRF450R. The fork is approximately 30% lighter in compression damping than a KTM 1190R, while having a similar spring rate, so it’s aimed at a rider who wants a softer feel. As I said at the start, many AT owners love their bike, this is what we do for riders who want more performance and are happy to forgo the soft feel.

Our modifications to the stock cartridge are aimed at giving more damping support, so you lose the floaty feel. Brake dive is significantly reduced, feel is improved. You get more feedback so you know where the front tyre is. Getting some air becomes fun, not crashing back to earth.

I don’t change the stock springs for riders under 100kg. it’s a lack of preload that causes the sag, not a light spring. For heavier riders, we offer linear springs in 0.60,0.70,0.75kg/mm

What the stock cartridge can’t do. It’s limited on preload adjustment, only 10mm. Ohlins has 18mm. The compression adjusters at the base are quite ineffective. The rebound adjusters only have a small usable range, ½ to 1.0 turn out. They may have 3 turns but the adjustment it to course.

CRF1000L Upper Fork Tubes

The internet had a melt down over AT upper fork tubes wearing the anodising off where the lower fork clamp is, lots of talk of over tightening the lower clamp causing the wear. We measured it, checked every set of AT forks that come in the door and talked to Honda.

First, it’s not as widespread as the rumour mill claims.

Second, the wear is above the lower clamp, so it’s not tightening torque. The wear happens on the front of the tube so it’s the pressure of the bush causing the wear. If you spin the top tube 180 degrees the wear still happens at the front.

Third, the riders who seem to have the most issue are road rides where the fork sits in one place for a long time. Offroad riders don’t seem to have near as many issues.  

Our answer to this is a performance coating called Kashima Coating. It is only available in Japan, Kashima coating consists of lubricating molybdenum disulfide deposited via electrical induction into the billions of micro-pores on the surface of hard-anodized aluminium to provide better lubrication and less abrasion and wear. This process can take some time to get done due to shipping time frames ex-Japan. We have 6 sets of exchange Kashima coated fork tubes in stock to allow a fast turnaround because no-one wants to have their bike in pieces for long periods of time.

In order for Kashima coating to be performed the fork tubes must not have any significant scratches or gouges as Kashima is microns thick, it won’t fill holes.

Of course, another option is to get a complete aftermarket fork such as the Ohlins CRF1000L Africa Twin Adventure Fork.

Africa Twin Common Rear Complaints

The stock 46mm Showa shock is not a bad unit but set up very lightly for road touring with an emphasis on comfort. Although the shock spring rate (8.3kg/mm) is OK for an 85kg rider (According to the Australian Bureau of Statics the Average Aussie male in 2013 weighed 85.9kg add-on 10kg of riding gear, hydration system and possibly some luggage plus the fact that we aren't all average there is often a need for a heavier spring), the shock spring preload needs to be increased dramatically to help keep the ride height up.

Result Of Testing On The Honda CRF1000L Shock

Generally, our first step we take when we get a shock is to listen to a wide variety of riders, what they think, good and bad, then run the shock on the shock dyno and identify the rider feedback in the graphs so we know what we need to concentrate on.

Part of our testing process is benchmarking against aftermarket shocks to see where their R&D took them. Remembering some riders are very happy with the stock shock we can end up with 2 or 3 settings that give different damping characters depending on if you are majority road touring with some gravel, mostly adventure touring or ride it like a CRF450R.

The downside of the stock shock is an ineffective compression adjuster and a spring preload adjuster that is stiff to turn for springs heavier than stock, the 8.3kg/mm. the 9.0 we often use is OK but a 9.5 or 10.0 shock spring makes adjustments hard. It’s 1mm of spring preload for 2 adjuster turns. The Ohlins unit, by comparison, is 3 turns of the adjuster per 1mm of spring preload, so it's easy to turn with any spring.

We have done some extensive experimenting with stock preload and here is a snippet of our results. To help you interpret the graph below are a few key notes to be aware of:

  • If you have the bike up on a lift, the suspension is "topping out", completely hanging free. This is called the free length and it's as long as your suspension gets.
  • Now if you put the bike back on the ground, the suspension will drop a little due to the weight of the bike. The amount it drops is called static sag.
  • And if you then sit on the bike, the suspension will drop some more due to your weight. Even further if you carry a lot of gear. The amount that the suspension has dropped from the free length is called the rider sag.
  • A "classic" sag setting is 10% shock travel for static sag and 30% shock travel for rider sag, so here are the numbers for the CRF1000F: a total of 218mm shock travel, so an ideal static sag of 21.8mm and an ideal rider sag of 65.4mm.

So, as you can see from the graphs, the sag from stock is excessive. With no preload on it, the rear suspension is almost a third of the way through its travel before anyone even sits on the bike. When it's weighted up, with so much less shock travel to absorb any big ruts and thumps, the shock skips around and gets harsh quickly. We have added a spacer/collar to the spring to increase the initial pre-load, and now it's much closer to classic ride height numbers, leaving more shock absorber travel and a useable preload adjuster.

Simply, stock spring for under 80kg no gear, 9.0kg/mm for most riders up to 120kg, 9.5 and 10.0kg optional, depending on luggage. The Ohlins comes with a 95N (about 9.5kg/mm) stock.

Racing Setup Sheet

Print and take this to your next track day. Without tracking the changes you make, you are probably going around in circles.

Bike Maintenance & Repair

Riding your new bike. It's one of the best feelings in the world.

Click to download orginal article in Transmoto Magazine or scroll down to the bottom.
Courtesy of Transmoto Magazine.


MOTORBIKE DIY MAINTENANCE & REPAIR

What was once your brand-new pride and joy is now slumped in the shed looking like a refugee from the recent Queensland floods. Guess it’s time to rekindle the love affair…

A new bike in the shed is a wonder every rider needs to experience at least once. The smell of never-roosted tyres, the shine of un-scratched plastics and the tack of virgin handgrips are pleasures that often have the lifespan of a Mayfly (those lil’ suckers sometimes only live for half an hour – not ideal pets, then!). To increase this fragile existence, many riders will perform the ‘New Bike Beer Night’ with like-minded homosapiens, talking for hours about the shape of a bracket or the curve of a lever. It’s at this time that the ‘Man-shed’ truly lives up to its lady-mystifying billing.

But when does new become not new, then used and then secondhand? Putting around 10 hours on a bike will test the love you feel for her and by another 10-20 hours (about six month for most of us), it definitely feels as used as the fake ID in a drunken teenager’s pocket. So what happened?

From the moment your take your tentative first ride, Mother Nature is trying to turn your moto-love back into whatever it was made from. Alloys corrode, steel rusts, rubber goes brittle. The sun and UV radiation aren’t on your side, either.

So how do you keep the new bike feel and look while the hours rack up? Luckily, there’s not a lot of cash that needs to be parted with; just shed time and some simple tools. The freshen-up of this Honda CRF250X would cost between $200 and $700 in parts, depending how far you go, and about a day on the tools.

BASIC BIKE MAINTENNACE

A CLEAN BIKE IS CRUCIAL

It’s amazing when a bike is wheeled into a workshop dirty. Most owners reckon ‘She’s clean as, mate!’ Obviously, we all have different views on ‘clean’ but if it doesn’t resemble showroom clean, you’re only fooling yourself.

Dirt is not an inert substance – it’s minerals wrapped-up in a bit of moisture. The longer you leave it on, the more corrosion occurs. That’s why race teams wash their bikes straight after the last moto, even though it’s dark, cold and everyone just wants to go home. They know that dirt left on the bike for even a day or two will dull the shiny bits and make the job harder. As we all don’t have a semi to wash out of, why not drop by a 24-hour self-serve carwash on the way home? You’re already dirty and the bike is probably on an open trailer and easy to get to. They even have foam spray!

  • Soapy tank wash. Truckwash can be high in alkaline, which is deadly for anodized alloys and can strip the cadmium plating off spokes and bolts. Use a bike-specific wash.
  • Dirty bottom. As most of the dirt collects on the underside of your bike, it’s vital to lean it over and wash its undercarriage. If you have a plough for a bashplate, remove it, clean well behind and use Dzus fasteners for quicker baths next time.
  • Strip and plug it. Getting the seat and tank off it essential, especially if you’re adjusting valves. Clean well before opening any covers, as engines and dirt get on like flood victims and bad insurance companies. Buying and using an air filter cover and exhaust plug are wise investments.

MAINTAIN YOUR BIKE'S DAMAGE-PRONE PARTS

Yamaha’s WR-F and Honda’s CRF both come into Oz with a headlight and tail light only, and the ADR-legal stuff is added here, via a piggy-back harness.

Dirt bikes are road-legal off the showroom floor but blinkers, horn, mirrors, speedo and the associated wiring are all damage-prone in the bush. It’s not difficult to simply remove the ADR parts and get the bike back to how it was manufactured, with just front and rear lights and a brake-light switch. Sure looks cooler and will save you heaps in a crash, but not exactly legal. But then, neither are doing high-street wheelies and roosting your mates.

Having been pulled over a few times by the law, I can tell you that with working lights and registered bike, a responsible, licenced rider is unlucky to get booked. However, roosting cars in the gravel by the road will see you with a nice fat fine and the scorn of all riders who try to debug the myth that we are all brainless hoons looking for an early meeting with the big fella upstairs.

When you get decals made, get your bike’s registration plate printed on the rear guard. Illegal as a priest in kindy, but better than the RTS-issue alloy item cracking and falling off, or ripping you open like a filleted fish.

If you really must run a speedo, use a pushbike number – with the sensor on the rear wheel. This lessens the chance of wiring failure and the wheelspin factor is not as bad as you’d think.

Lastly, keep it quiet – 94Db should be considered a maximum, so that means mufflers – like the DEP S4 and FMF Q-Core range – not open race pipes. The stock mufflers on some models are very good, with WR-Fs and EXCs excellent.

MAINTAIN YOUR BIKE'S BEARINGS

Bearings have a hard time on a dirt bike. Manufacturers don’t help by using open (no external rubber seal? Units in wheel bearings. NTN bearings are a very respectable brand and their LLU sealed bearings are perfect for dirt bike wheels, drivechain rollers and brake pedals, providing excellent movement, along with great dust and mud sealing properties.

Linkage and swingarm bearings are not hard to disassemble and grease, so do them after the initial break-in period and then every 40 hours. If your world turns to rust, companies such as Pivot Works and All Balls offer great replacement kits complete with spacers seals and bearings.

There is nothing difficult about removing linkages for maintenance – your bike is basically just a big Meccano set. The key is a well-washed bike, a good stand, a brightly lit work area and a modest toolkit. A swingarm-out type grease-up would take most people a couple of hours.

Steering head bearings can ruin a great ride. Any corrosion or brinnelling (small wear marks from sitting still or small movements) means it’s replacement time. As prevention is better than cure, this is best fixed in the shed and not bodged out on the trail.

CHECK WHEEL BEARINGS

Wheel bearings have a hard life as we only tend to look at them once the poor buggers have collapsed. It’s no fun wrecking a bearing on the trail and even worse when you realise how cheap and easy they are to replace. The common bearing check is to feel for movement by grabbing the top of the tyre and rocking the wheel side to side. If you feel play, it’s new bearing time. This movement also causes brake pad ‘knock-off’ as the pads are puched back by the rocking disc. Wheel bearing replacement is a simple process of removing the outer dust seals, moving the internal spacer tube between the bearings over slightly and driving the bearings out. Rear bearings can be retained by a locking collar or clip so check before taking a run-up with hammer.

If you can push down on the seat and the suspension stays down, it’s normally the linkages, almost never the shock at fault. To remove the whole rear suspension, place the bike on a stand and take the seat and tank off. The rear subframe can stay on if it’s too hard to remove (like on a Suzuki DR-Z400 where there’s a mass of wiring); just remove the bottom bolts and then pivot it up and use a tiedown (stretching to the bars) to hold it up. Remove the rear wheel, take the chain guide off and drop the rear caliper off the swingarm. Two bolts will get the shock out and that will give easy access to remove the linkages. Drift the swingarm pivot bolt out and inspect it. Don’t allow the roller bearings to drop on the floor. Any rust in here is bad, missing rollers worse. To replace the press-fit swingarm bearings, you can use a vice as a press with a few sockets to act as press tools.

CHECK STEERING HEAD BEARINGS

The steering head bearings are checked by holding the front brake on and rocking back and forth. Any clunks means it’s time to tighten or replace them. If you do not know the condition of your steering head bearings, disassemble and check them. The fear you feel when blasting towards a corner, only to have the steering head locking up because watching another episode of Two and a Half Men was more important than working on your bike, is somewhere between ‘Oh shit’ and ‘I wish I packed my PJs for the hospital stay’. Removal is simple – get the front wheel off the ground, remove the bar clamps (no need to take the bars, throttle or controls off) and loosen the steering them nut. Remove the front wheel and forks. Loosen the bearing adjuster nut and, volia, the bottom triple crown slides out. Gaze in horror at the lack of lube and vow never to be such a clack grease monkey again.

“Gaze in horror at the lack of lube and vow never to be such a slack grease monkey again!”

MECHANICAL TWEAKS

ENGINE SERVICING

In this modern four-stroke world, if you have a two dinger you may well think yourself lucky. But 4-stroke servicing is simple. First rule is change the oil. The second is to perform the first rule often. That’s 500km max for spirited trailriding (or about 15 hours). Cut that in half if you race. Check the valves every 1000km (30 hours), 500km if racing. Think about a piston at 50 hours for a 250cc and 100 hours for a 450. Ideally that would be it, but occasionally engines drop (break) valves, bearings fail, oil galleries block and well-meaning owners put oil filters in backwards while trying to look after their bike.

A two-stroke requires more regular engine work but is less prone to wallet-busting disaster, unless you forget to mix oil with the go juice.

MAINTAINING SPOKES

Spoke used to give us all hell but that’s almost a problem of the past. On the initial run-in, they stretch slightly as the wheels ‘settle’, requiring a going-over after each ride. Spokes don’t need to be dead tight – it’s easy to discomfort the nipples, especially if they are aluminium. The best way to tighten them is with a spoke torque wrench, as the setting is quite low compared to what you think they need. The downside of not maintaining them is damage to the rim and hub from the spokes moving around. The telltale for this is a blackening of rubbed alloy dust due to the wear of the hub and/or rim. Worse yet is a complete collapse, but that’s relatively rare outside of MX use. The most common problem is a broken spoke puncturing the tube. This can be cable-tied up on the trail to get you home.

CHANGING SUSPENSION FLUID

We all know about changing engine oil but spare a thought for your suspension fluid. There’s about 300cc of oil in most shocks and by the time the first 15 hours are up, it’s looking more like a milkshake. That’s because the factory bleeding process is never great, plus the bladder that holds the gas is permeable, meaning that the oil slowly ends up full of gas. Within a year of the shock being built, it’s overdue for an oil change. Not a big cost, as it’s just a fluid change, about $90-120 from suspension tuners. The forks are similar, normally being built a month before the motorcycle is assembled. The fork seals and dust wipers stretch on the tubes over time, so don’t expect your first set to last – but the second set is usually good for 40-50 hours, the working life of the fluid.

MAINTAIN YOUR BIKE'S FRAME & PLASTICS

Bless the alloy-framed dirt bike! In years gone by, you had to keep a can of touch-up paint for the steel item and even then it had more bare metal showing than paint by sales time. Now a Scotch Brite pad takes care of the dull, rock-blasted alloy – just give it a gentle rub while you wash (the bike that is, not you). Same treatment for the engine sidecovers.

The plastics also look faded and rough after a very short time. Need more reason to get a full decal kit? They don’t scratch, resist fading, have your name on them (in case you forget) and can give your ride a custom look. Prepare to say ‘sayonara’ to $200-$400.

Grips get torn so replace them as they’re under $20. Levers bend, but stock levers are forged and can be bent back, though cheap aftermarket items are cast and snap like a chicken being eaten by a hungry croc. Some riders like the multi-bending levers from ASV and the like, but they’re pricey at about $80 each side.

HANDLEBAR BASICS

Bars get cluttered-up with mirrors mounts, switch blocks and kill/start buttons. Head to a bin and get rid. Mount Barkbusters off the top triple clamp, then they won’t spin round in a crash. Fix them horizontally so they cover your hands and won’t steer the bike when hitting trees. $100 will buy you some good replacement bars with a more personal bend and then stick your new grips on with spray adhesive. Remember to lube the lever pivots.

PUNCTURES ARE AVOIDABLE

Ditch the stock thin tubes on the first change and put some heavy-duty ones in the resist pinchflats – and drink less beer to offset the weight increase. Lube the spokes while you have the tyres off. Rim tapes are okay until they stretch – Duct tape is ok, too. Treat yourself to some decent tyres – ones that last forever rarely offer decent grip, and you do want to have fun, don’t you?

CLEAN AND OIL THE CHAIN

No more Duckhams’ chain was in 2011! Clean the chain with a stiff brush then oil it as soon as you have finished washing the bike. I like gold chains when you go for a replacement (goes with your gold teeth and spinners on your Bemmer, eh Doley? – Ed), as they have great corrosion resistance and are usually only 15 bucks more than an uncoated chain.

 

Nuts & Bolts

We've all seen plenty of them, but do you really know the physics of how they work?

Click to download orginal article in Transmoto Magazine or scroll down to the bottom.
Courtesy of Transmoto Magazine.

On The Tools Tech Series:

ISSUE 1. SUSPENSION MODS How to get the most from your suspension budget.

ISSUE 2. GEARINGUnderstanding sprocket combos and optimising gear ratios.

ISSUE 3. CARBS & EFI - Clever tuning tips to get your air/fuel ratio right.

ISSUE 4. NUTS & BOLTS - How to remove broken bolts & get the right torque settings.


HOW TO REMOVE BROKEN BOLTS & GET THE RIGHT TORQUE SETTINGS

Fasteners keep your bike in one piece, so here’s how to tighten, maintain, remove and repair them.

The work of Mr. Murphy – “if anything can go wrong, it will” – applies to the bolts, nuts and fasteners of your motorcycle. Easily overlooked, they wreck more rides and cause more race losses than any other mechanical DNF. Without fasteners, your bike would be a pile of parts on the floor.

While the topic of fasteners concerns all materials, most are metal bolts. There is an interesting field of quantum mechanics that could fit in here, but let’s skip to the practical part, as there are a few characteristics of metal you need to know. Metal is a conductor of not only electricity, but heat. Metals can bend a long way before they break. Metals are also elastic; when a load is applied, they can deform and return to their original shape unless their elastic limit has been reached. Lastly, they are strong, with characteristically high tensile strength.

Bolts have a tendency to come loose, seize, break and corrode if not maintained and cared for. So the following few pages will help you to keep that bucket of bits you call a motorcycle together without some of the pain your forebears experienced.

TORQUE DEFINITIONS

LOAD is the overall force applied to a fastener or structure, whether resisting an externally applied force or supporting the weight of a mass.

STRESS is an applied force that can cause the deformation of a fastener.

STRAIN is the change in dimension of the fastener body as a result of stress.

STRENGTH is the ability to resist forces.

TORQUE SETTINGS

When you tighten a bolt, two forces are at work. Tension stress (stretching) occurs when the head of a bolt contacts the material it is to be tightened against. This form of stress – the use of the elasticity of the bolt – is what exerts a clamping force. A secondary shear (torsional) stress occurs as the friction from the threads and under the bolt head is overcome – a stress that is undesirable due to its inconsistent values – and is unavoidable.

This is where your torque wrench – used to achieve the correct torque setting – gets lost. It can’t tell the difference between tension stress and shear stress. Dirt, rust, plating, oil, anti-seized, Loctite and damaged threads will all have a big impact on torque readings, and therefore the bolt stretch you finally achieve.

How big is the impact? At worst, with dry and unplated threads, 50% of the torque applied to the bolt will be absorbed under the bolt head and 40% by friction on the threads, leaving only 10% to apply preloading to the bolt.

So what can be done to avoid this? There is not a lot of maintenance required on a bolt, but no threads work well when dirty or rusted, so keep them clean. A wire wheel on a bench grinder does a great job of cleaning threads. While some light oil is okay as a lubricant, a zinc – or cooper-based anti-seize is excellent for swingarm pivot bolts, chain adjusters and exhaust bolts. If you require retaining properties, use Loctite, which we will come to later.

Although using a torque wrench is necessary on critical bolts, for non-critical areas, feel is often the best judge; especially on older bolts. If you feel a bolt “give” while you are tightening it, replace it.

REMOVING BROKEN BOLTS

So the worst has happened – the bolt head has snapped off. If it’s got a nut on the other side you can simply remove the broken part, but if it’s in a part – and left a section of the bolt inside the thread – the problem is much more serious.

It’s important to look at why the fastener failed for future reference. Was it over – tightened? Was it loose and subjected to shear loads? Was the fastener the wrong type? In the vast majority of cases the bolt will have stretched past its elastic limit on the last installation and broken on the narrowed ‘waist’.

This is where the maintenance you have done previously kicks in. If the threads are clean and have wither anti-seize or Loctite on them, it will be relatively easy to remove. If the bolt broke during installation due to high friction on the threads, you are in for some fun getting it out!

ROUNDED HEADS

There are a few simple rules with all fasteners that will prevent rounded heads. Use the rIght size tool – this means no 7/16 spanners on 11mm bolt heads. Also select the correct type of tool (see ‘Tool Selection’ on the final page). The tool also needs to be square on the bolt or nut. A poorly held open-ended spanner is the cause of many wrecked bolt heads.

What to do if the bolt head is rounded? A single-hex socket will remove most damaged bolt heads. If this fails, the bolt is considered junk, so hammer an old single-hex socket onto the head. Another option is to weld a nut to the head. The heat from the welder pumped into the threads can help loosen it, too.

BROKEN-OFF HEADS

Broken-off heads are traditionally solved with an evil device called an ‘Easy Out’. Anyone who has ever snapped one will know that there is nothing easy about drilling a broken, hardened Easy Out from a hole. It takes a cobalt drill or diamond-hard disintegrator, heaps of lubricant and some words your mother would rather not hear.

There is a better way. Drill into the centre of the broken bolt with a left-handed drill, aiming right down the middle. In the process of drilling, you may very well spin the bolt out – as the drill is turning the bolt in an anti-clockwise direction, therefore loosening it – and it’s job over! Start out small, be super accurate with finding the centre of the bolt and move up in drill sizes, always trying to shock the bolt out with sudden bursts of power. If this doesn’t work, move to the next step.

STRIPPED THREADS

If the thread is butchered or you have drilled out a broken bolt with a left-handed bit to the extent that you are into the threads, an insert needs to be fitted into the hole to provide a solid, clean thread for the next bolt to go in. That is, unless you are a total Neanderthal and just tap a thread the next size up.

The traditional thread insert is a helicoil, but they are known to jump threads and lock onto bolts, winding themselves out. A much better alternative is a ‘time sert’, which is not as well known. This solid-threaded insert – that is much the same as a helicoil to fit – is locked into the hole with a broach, and is much more sturdy. For other options, see the ‘Tools’ sidebar.

Whichever method you choose, get it straight and pay attention to the drilling size suggested in the tap. And, if you’re out of your depth, find someone who knows what they are doing.

TOOLS

REPAIR METHODS

We have discussed helicoils and time serts elsewhere, but there are other methods. Lock serts and big serts are also options for when things gets ugly. For example, not drilling down the centre of a snapped off bolt means the drill drifts quickly into the soft aluminum, so a 6mm hole will soon become an 8mm. A big sert uses a ¾ UNC 16 thread – that’s close to 10mm – so you can ‘fill the void’ and save a disaster with a super strong repair.

TORQUE WRENCHES

When using a torque wrench to reach the correct Nm setting, be careful to ensure you use the metric – as opposed to imperial – scale on the wrench. The bending beam-type wrench is reliable and accurate, as are the Australian-made Warren and Brown wrenches. Don’t use socket extensions, as they can throw off the reading by twisting and absorbing some of the force. Creep up on the torque setting over four separate stages, and check the setting twice as the shear force will dissipate after a few seconds.

TAPS & DIES

It is handy to have a collection of taps and dies in your workshop, as rusted or dirty threads are always a problem on a dirt bike. There are only a few main sizes you nees for most jobs. A handy selection is 6x1.0mm, 8x1.25mm and 5x0.8mm. Buy good quality tools, like Aussie-made Suttons, as a cheap tap can do more harm than good. When chasing out a thread, if you start to remove metal, stop and check the size. And if the thread is deformed on the male or female thread you are chasing, replace it.

LOOSENING BOLTS

As we’ve explained, it’s mostly the tension created by the elasticity in a bolt that keps it tight. This produces a dilemma for many fasteners on a dirt bike, as they are not pulled up against hard surfaces. Plastic, within its low tensile strength, will deform, causing the fastener to loosen. This is why the alloy or steel inserts in your shrouds, guards and seat perform a crucial role in keeping the bolt tight. It’s amazing how some manufacturers ignore this fundamental principle and use plastic as a loaded part. The Euros have been onto a good concept for a while, using no inserts in the tank and a coarse thread bolt straight into the plastic. It looks rough at first, but works well as there is next to no load on the radiator shrouds.

Through vibration and repeated stress – whatever the material – some bolts will work themselves loose, so here are the main methods of keeping things tight.

LOCTITE

For keeping most fasteners tight, it’s best to use an anaerobic (cures in the absence of air) liquid thread retainer, such as Loctite. A drop of the right grade applied to the tip is all you need to keep a bolt – correctly tightened – in place.

Oil and dirt will still lessen the effectiveness of any anaerobic retainer, so you still have to clean the threads before applying it. A squirt of brake-clean from an aerosol can does a good initial clean, but there are Loctite primers in aerosol cans if you’re a perfectionist.

As per the guide below, there are different grades of anaerobic retainer, and using the wrong product can be disastrous. Ever tried be remove a bolt that was primed and coated with permanent assembly Loctite? It’s strong enough to cause a bolt head to snap or make tank inserts spin.

LOCTITE GRADE GUIDE

222 243 263 290
Low strength. Designed for fasteners that come apart often, such as radiator shrouds and guards. It won’t hold bolts so tight you need heat for disassembly, but it will stop corrosion and lost parts. For general-purpose use. It can still be disassembled with hand tools and – like all Loctite – will virtually eliminate galvanic corrosion between steel and aluminum. For permanent assembly. Will require a heat gun and 400 degrees plus for it to break loose. Use it on the axle feet of lower fork tubes and shock yoke shafts. For use when disassembly is not required! Great fos spoke nipples, as it allows you to tighten them up, but stops them from loosening. It also prevents corrosion.

 

LOCKWIRE

Lockwire is not just for grips, but can be used on footpegs and to mechanically keep bolts tight. White it comes to sizes 0.020” through to -.040”, the 0.032” in 302-grade stainless steel will do everything tou need on a dirt bike. A 1lb tin of it should last you 10 years, and the fancy wire-twisting pliers are not necessary if you follow some basics.

Cut the wire long enough to do the job, and use smooth-face plyers for twisting. Pull on the wire while twisting to take up the slack, but don’t make it tight. Don’t nick the wire with pliers, as increased stress will cause it to break. And remember to pick up the little off-cuts, as they are sharp and can be disastrous if sucked into an engine.

LOCK NUTS

Spring (lock) washers have no place on a motorcycle. Why? Try compressing one with your finger. By the time the bolt has backed itself out enough for the spring lock washer to be effective, the bolt is loose and on the way to falling out.

Instead, put a flat washer under the bolt with Loctite. Also, integrated flange-type bolts are now commonplace on motorcycles, and don’t need a washer. ‘Nyloc’ or ‘conelock’ nuts are great for reducing the change of loosening, but should be replaced after every couple uses.

Folding tab washers should be avoided if possible. In order to be able to bend the tab over, the washer must be relatively soft and susceptible to cyclic stress, and can squeeze out.

BOLT TECH

Inspired by the nautilus shell, threads have been with us since ancient Greece, so say thanks to Archimedes from 200BC. Then after WWII, the thread angle was standardised to 60 degrees, as the USA, Europe and the UK were all on different standards. This became uniform in both metric and imperial standards. The main difference between a metric and imperial thread system is the description for thread pitch. Metric thread pitch is measured in mm (1.0, 1.25 and 1.5mm are common), and imperial threads are measured in threads per inch.

Australia has adopted the international ISO bolt standards into the Australian Standards. However, most bolts sold at the hardware store are cheapies that do not comply, so avoid them like the plague. If buying bolts from a fastener retailer such as Blackwoods or Coventry, request a Letter of Conformance to ensure the bolts you are using comply.

Also, critical triple clamp/handlebar/axle bolts are designed for a specific purpose, so it’s worth the measly extra cost of buying genuine fasteners when you consider the cost of it failing.

Finally, bolts are tested for tension (stretching) strength and hardness. One critical point to remember is that ‘stiff does not imply strong’. For example, a bolt made of glass would be very stiff, but could not stand any impact load – it is not strong. Using that theory, different grades of bolts have different tension, compression and shear properties, and bike manufacturers use different grade bolts for different purposes. Therefore, it is important to use the correct grade when replacing a bolt. Metric fasteners are stamped with their grade, either 4.6, 8.8, 10.9 or 12.9, from weakest to strongest. Also, bolts in critical applications should be replaced periodically.

OTHER NUTS & BOLTS ESSENTIALS

CABLE TIES

What did we do before cable ties? String? An aircraft spin-off from the mid-’50s, cable ties are great for holding things in place. As there are no strict SAE manufacturing standards, it’s best to go for a brand name like Ty-Rap if the job is critical, as cheapies can skip teeth and crack. And if the cable tie breaking is going to cause personal injury, it’s not the right application for a cable tie. There are tensile strength ratings, but UV rays really hurt nylon, so it’s better to use them under tanks and seats where they don’t get direct sunlight. Instead, hoseclamps can be used in these applications.

ADHESIVES

People use all sorts of adhesives on their grips, from hairspray, paint, araldite, grip glue, contact cement and gorilla glue. Contact adhesive in an aerosol can is usually the most convenient and effective. If you are a real grip-destroying gorilla, 5 Minute Araldite is good, too, but when finished you need to cut the grips off like peeling a banana. Anything that dissolves in water – such as hairspray – is no good; two throttles aren’t cool. The only other adhesive in your toolbox should be white ThreeBond liquid gasket cement. It’s also sold as an OEM sealant, and it’s the only one worth having. Use it sparingly, like any gasket cement.

TOOL SELECTION

A socket (1) should be your first choice of tool, followed by a ring spanner (2). Aside from a shifter (4), an open-ended spanner (3) is the least preferable tool for tightening bolts, as the ends can separate (shown in the main picture). There are two types of sockets and ring spanners – six- or 12-point – known as single hex and double hex. A six-point has six flat edges, while a 12-point has 12.

BOLT STRETCH

As you can see in the picture, the bolt in the foreground has deformed and is skinny through a section of the thread length. This was caused by the bolt being stretched past its elastic limit. It can no longer function properly, and needs to be replaced. The bolt at the rear is straight, and therefore hasn’t been stretched past its elastic limit.

AFTERMARKET

For non-critical applications such as tank and seat bolts, there are a few companies selling bolt kits with the type of flange-head bolts that don’t require a washer. The quality can be good or bad – you will know the first time you tighten one. A good bumbag assortment for Japanese bikes is a collection of 6x20mm, 8x30mm and 5x40mm bolts. A gear lever bolt and a top shock bolt are also required for KTMs. However, a better plan is to spend some shed-time before you leave home, so you don’t waste time working on your bike when you could be riding.

 

 

Free Suspension Setup Tips

Can you set up a bike’s suspension without spending a cent? You can if you know where to look…

A quick bike is one thing, but if it handles like a three-wheeled billycart or smacks the rider around like a naughty nurse, all that perceived performance is lost.
In this article we look at optimising what you have without cracking the credit card and offer some good, basic starting points.
Courtesy of Australasian Dirt Bike Magazine.
 

Air Filter Service

Keep the dirt & dust out of your bike's lungs effectively.

Click to download orginal article in Transmoto Magazine or scroll down to the bottom.
Courtesy of Transmoto Magazine.


DIY WORKSHOP SERIES

ISSUE 39.  WORN GRAPHICS - Bring back that new bike feel...

ISSUE 40. WIRING DISASTERS - Tame the wiring harness jungle...

ISSUE 41. BRAKE SERVICE - Start looking after your stoppers...

ISSUE 42. WHEEL BEARINGS - Roll clean, and free...

ISSUE 43. CHAIN & SPROCKET - Tired old teeth slow you down...

ISSUE 44. CONTROL REFRESH - If you can’t put your finger on it...

ISSUE 45. DON’T GET DUSTED - Keep that box clean...


ENGINE AIR FILTER SERVICE GUIDE

Cleaning your bike’s air filter ranks right alongside changing your oil as the most important maintenance task you can do to properly look after your engine. Short of writing off your pride and joy in an accident, the quickest way to destroy a perfectly good machine is an iron lung-full of dust being sucked through your cylinder ... because a full rebuild is a highly likely scenario if you don’t maintain your air filter.

Most modern bikes come standard with high-quality foam filters, but it’s well worth investing in two or three spares. This allows you to keep a rotation going and do all the dirty work in one batch. Old filters can also start to break down over time, so invest in new ones every couple of years.

Filters always get dirty wherever you ride, so get into the habit of checking your filter before each and every ride. Ideally, change the filter between every ride, or at least try to ensure it’s seated correctly and is relatively clean.

Nick Dole from Teknik Motorsport explains how a filter change is properly done.

TOOLS YOU’LL NEED

Spanners, T-bars and Socket Set

Gloves

Rags

WHAT A FILTER CHANGE WILL COST YOU

Labour: 20 minutes
Filter Oil: $25

1. REMOVE THE FILTER

Once you’ve removed the airbox lid – or seat – necessary to access your filter, grab a clean rag and wipe any dirt away from the edge of the filter and from around the airbox. This prevents crap accidentally falling into the air boot when the filter’s out. Then, remove the fastening screw or bracket and pull the filter out.

2. INSPECT THE AIR BOOT

With the foam filter out, grab a torch and have a good look inside the black plastic air boot leading to the throttle body or carby. Wipe your (clean) finger and check for any dust. Even the lightest of coatings may indicate that dirt has bypassed the filter, which could signal trouble for your engine.

3. CLEAN & RINSE THE FILTER

Pull the foam filter off its plastic frame, and soak the filter in a kerosenebased solvent (petrol can deteriorate the foam and glue). Once the oil has broken down after a minute or two, use your fingers to work out any trapped dirt particles from the foam elements. A rinse in warm soapy water will ensure a thorough clean.

4. DRY THE FILTER

Ensure the filter’s dry before oiling. To speed up the process, you can place it on newspaper or paper towel or hang it on a fan, but by far the most efficient way is to hit it with pressurised air. Avoid hot air guns, though, as this can melt or degrade the glue used in the filter’s construction

5. OIL THE FILTER

Air filter oil is seriously sticky stuff, so the cleanest way to oil a filter is to wear gloves to work the oil through the filter, or put the filter in a plastic bag to mush the oil through. Ensure that the oil has passed through all of the foam pores. Aim for an even coverage, but with any excess oil squeezed off – otherwise your bike’s air intake may be unnecessarily restricted.

6. RE-INSTALLATION

With the filter cleaned and oiled, reinstall the filter on its plastic frame. it’s a good idea to leave the oil to set for a few hours before re-installing on the bike. now put a generous layer of grease around the airbox seat and the sealing surface of the filter. This will prevent any dust entering around the filter. Ensure the filter is seated neatly and fastened.

Filter Skins

Air filter skins are a thin, stockinglike material that is designed to fit snugly over your air filter to act as a kind of pre-filter. The idea is that the skin can be pulled off when dirty, leaving your foam filter largely clean and extending the intervals between filter changes. Skins are cleaned in the same way as filters. They are great for multiday trailrides, but not everyone uses them, as they restrict airflow and require special care to ensure a good seal between the filter and airbox.

Cleaning the Airbox

Over time, your airbox will get a build-up of grease and dirt. Degreaser will help, but the best way to really get your airbox clean is to pull the whole subframe off, together with the airbox, then hit it with a pressure washer. When re-installing the subframe, be particularly careful when fitting the air boot back onto the throttle body or carb – a loose or misaligned boot will suck in unfiltered air and kill your engine.

 

Using Your Clickers

Ever adjusted your suspension? Scared you'll stuff it up if you make any changes?

Click to download orginal article in Transmoto Magazine or scroll down to the bottom.
Courtesy of Transmoto Magazine.


YOUR GUIDE TO CLICKERS

Welcome to Transmoto’s entry-level suspension guide, aimed squarely at riders who’ve never threatened a fork leg or shock reservoir with a screwdriver.

If you've never touched your clickers, then your suspension could be better than it is, for free. Understanding the basics of suspension and adjusting them using the built-in (on most bikes) adjustable suspension means you could be riding faster, enjoying your riding more, and avoiding those aches & pains you get after a blast. Have a read of our basics guide, and tinker away!

It’s a crazy thought but in an ideal world, your bike would have no suspension. Why? Because the movement of both fork and shock affects wheelbase and geometry, which, in itself, affects handling. But bumpy terrain is what riding off-road is all about, so it’s important you not only embrace your suspension, but learn to love and trust it, too.

Getting the perfect set-up can be a costly and time-consuming activity. Luckily, just a few clicks here and there on your stock suspension can make a world of difference. That’s why they have the adjustment, after all.

Okay, that’s great if you know what you’re doing. But what happens if you don’t know rebound from retreads, compression from commotion or spring rates from starting gates? Normally, a technical article about suspension set-up would go into so much detail that you’d become a squareeyed page flicker before you can say ‘fork that!’ So let’s try a different tack...

We’re aiming for 80% knowledge here and the simplicity of a paper clip. So get that unused screwdriver out of the packet and prepare to improve the quality of your ride.

SUSPENSION BASICS

Let’s begin with some home truths. If your fork legs are pitted, rusted, covered in oil or move with the smoothness of a plastic knife through rock, then we’re both wasting our time here. Same goes for the shock. If your suspension’s not in good working order, no amount of knobtwisting will help. Expect to pay around $150 plus parts for an overhaul of your forks or shock.

Next up’s a little more personal. Enjoy yourself at Christmas, eh buddy? A bit too much beer and beef? Modern off-roaders are designed around a certain weight rider. For MX, the springs are aimed at a 75kg pilot; for enduro, it’s 85kg (and don’t forget the weight of your riding kit). So if Homer Simpson is your true sporting idol, best get your bike resprung. The cost of too much of the good life? Around $180 (each end) for the springs, and $250 for a re-valve to suit.

SETTING THE STATIC AND RIDER SAG

Sag affects all the good things in life and your bike’s no different. Before you head out and show that track who’s boss, take time to set the static and rider sag.

Static sag is the drop in height of the bike caused by its own weight. Put the bike on a stand so the wheels don’t touch the ground. This is the fully extended position of both the fork and shock. Take a measurement from both axle centres to a fixed point on the bike – axle to handlebar at the front and axle to a mark on the fender at the rear. Then drop the bike off the stand and measure the same marks again. The difference is the static sag and is usually about 10% of the total travel (actual measurement found in your owners manual or the ’Net). Then take a third measurement with you sitting on the bike, fully geared. The difference between fully extended and under the weight of your lard arse is the rider sag, normally about 30% of the total travel. If your bike is outside these figures, then the preload adjusters are your friends. Remember that the preload only alters the ride height and static sag and does nothing to affect the spring’s rate. The fork’s preload adjusters (if your bike has them) are normally the hexagonals on top of the leg that you wind in for more or out for less. On the shock, it’s the castleated collar under the spring that is turned with a special tool – one that never ever resembles a long screwdriver and hammer!

CLICKER ADJUSTMENTS

It’s nearly time for you and your sagged-up ride to conquer the world. But take a moment to think of what it is about your suspension that’s missing. Many riders fiddle with their knobs (we’re still talking suspension – focus!) just because they’re there and not because of a particular problem. If you’re happy with how your bike handles, the best advice is to leave it as it is and enjoy the ride.

Most suspension units can be adjusted in two different ways, though compression can have high- and low-speed settings. Compression (controls the rate that the unit contracts) is altered by the clicker adjuster, which can be either at the top or bottom of the fork (check manual), but always on the top of the shock. Rebound (controls the rate at which the unit extends) will be the other.

Now we know where the clickers are, what do they do? They simply act like a tap. Fully closed, they stop the flow and full open, they don’t. Typically, a clicker will have 24 ‘clicks’ of movement, though the usable range is normally between four and 20 clicks out. All measurements are taken from the clickers being fully screwed in.

TEST YOUR SUSPENSION SET-UP

As you’ll gain the most amount of time by going faster on a highspeed corner, your test circuit area shouldn’t be too tight and technical. Many riders place a tie-wrap around the fork stanchion (the shiny bit!) to see if they’re getting the full range of movement out of the unit. This is fine, but hitting a sharp-edge hard can skew this reading and make you think you’re using more travel than you do for 99% of your riding. As suspension set-up is always going to be a compromise, it’s best to find a setting that works for the majority of time rather than on one particular section. With just two clicks to be enough to feel the difference on decent suspension, the best advice is to start at the front of the bike (as the handlebars are directly mounted to them and your hands) with rebound and then compression before heading to the rear rebound and compression. Make sure you’ve noted the starting values of the units so you can periodically return to them as a reference.

After you’ve followed the chart (on the next page), you should have a clearer idea of how the clickers affect the bike and how to feel the direction of change when adjusting.

Now you have a basic understanding of your bike’s suspension, you’ll be more in control, less worn out and having a lot more fun than ever before. Job done, so go out and have more fun!

 

Kayaba & Showa Suspensions

Chances are that your bike, and probably even your car, has their suspension.

Click to download orginal article in Transmoto Magazine or scroll down to the bottom.
Courtesy of Transmoto Magazine.


JAPANESE SUSPENSION GIANTS KAYABA AND SHOWA

The world’s two biggest suspension companies – Showa and KYB – have a shared history that owes more to Japanese business culture than product.

Much of your bike, be it Japanese, European or made by a clog-wearing madman in a shed, has been assembled with parts procured from subcontracted and subsidiary suppliers. It might say Yamaha on the tank, but they won’t make every single item for their bikes. The front and rear suspension are one of the main non-manufacturer produced parts any machine wears-, but just who makes those items on your bike? For over 70 years, two Japanese companies – Showa and Kayaba – have been manufacturing bouncy bits for motorcycle producers around the world . Between these two, they supply the majority of the world’s surface transportation suspension.

But who are these shock giants? Showa is generally associated with Honda, as the big H is a shareholder in them. It’s the same deal with Yamaha and Kayaba. In the ’70s, when Kayaba was pushing into the US market, they shortened the name to KYB as the Americans had trouble pronouncing the full version. Gotta love them Yanks!

As you’d expect, both are big players in the business world, with Kayaba listing 1.7 billion Yen ($200m) in assets and Showa 2.3 billion ($270m).

JAPANESE-STYLE BUSINESS CULTURE

So how can a manufacturer that has a share in a suspension company reject their products and use a competitor’s offering? The answer is that Japanese society dictates that it’s not all about price, and that culture plays a bigger part.

The first level of Japanese business culture has its roots in the three main religions – Confucianism, Shintoism and Buddhism. All of which are above the natural world and our known universe, meaning that each follower believes that every single thing, including people, has its own soul or spirit. The Japanese call this Numen.

The second aspect is the circular grouping that forms the basis of the culture. These four circles are concentric, the nucleus being the family, second is the fellows, the homeland is the third and the rest of the world the fourth. Differing moral and ethical codes are applied to each group.

These circles are viewed as larger entities than the people in the group, and all connect to the Numen in a direct way. This takes us to the four circles of business relationships.

At the centre of culture comes family and closely-related business partners. The next circle includes long-time customers and financial institutions and traders. Each of these business associates are encouraged to maintain a balance between benefits to the group and debts owed to it. If a company does not offer enough benefits to counterbalance its debts, they are usually expelled from the circle – a bit like Ben Stiller in Meet the Fockers. The third group is Japan as a whole and the competing companies within it, although the ethics are one of free competition. The fourth and last circle is the world.

Western business has a difficult time understanding free competition. We are used to ‘crush your competitor’ and ‘business is war’, but this is not the case for traditional Japan.

The key is how the debts to each other are balanced. An example of how these debts work is if KYB helps Suzuki when they are in the midst of serious financial difficulties, then Suzuki will give the most preferential trade status to KYB after overcoming its difficulties. Suzuki will rarely change this policy, even when it finishes repaying its monetary debts to KYB.

Moreover, even if KYB’s products are relatively more expensive, as long as the price is not extraordinarily unreasonable, Suzuki will continue to purchase KYB’s product. If their products are not sophisticated enough to meet Suzuki’s standards, Suzuki will offer to help them improve their products.

The reverse is if Suzuki were to change the above policy soon after repaying its debt to KYB – such as buying cheaper products from Showa – then not only KYB, but also other corporations who have been aware of the process, will regard Suzuki as an untrustworthy company in their business community. Foreign companies, especially American ones, do not understand this ‘fairness’ context. They are more likely to switch immediately to Showa once the debt to KYB has been paid off.

This difference in the understanding of fairness is the main difference between Japanese and non-Japanese companies.

A BRIEF HISTORY OF SHOWA

Established in 1938 to produce landing-gear parts for aircraft, Showa switched to suspension units, hydraulics, steering systems, differential gears and other drive-related parts in post-war Japan, 1946. They listed on the Tokyo stock exchange in 1963 and established a US subsidiary in 1979. While there are now many manufacturing plants spread over Japan, Thailand, China, Spain, UK and Brazil, all the MX suspension is from Japan – as it’s at the high-end of suspension technology. To prove a point, take the shocks off a CRF230 and you’ll see the made in Brazil markings.

The mid-’80s was when we started to notice the Showa stickers and began drawing opinions on how the companies operated, based on their suspension packages from year to year.

Showa has always appeared to be the most conservative of the two companies, with great manufacturing capability and a bunch of motionless engineers in white coats. It was not hard to imagine how the feedback from the test rider to the final production suspension got a little lost in a sea of well-meaning corporate re-interpretation. Some of the most loved 43mm conventional (RWU) forks from the 1986-1987 CR250R were Showa’s with the newly developed cartridge fork. In contrast, some of the most horrible early ’90s USD forks were also Showa and the issues of rigidity in the tubes would not be fully understood for another decade.

A BRIEF HISTORY OF KAYABA

Shiro Kayaba founded Kayaba Industry in 1919, whose main products were aircraft catapult launchers, landing-gear and an interesting gyrocopter during WWI. The company was reorganised as part of the unconditional surrender of Japan after WWII and in 1945 began manufacturing automotive and motorcycle suspension components.

After listing on the Tokyo stock exchange in 1959, Kayaba expanded its product range to include earth moving equipment, cement-carrying trucks and ship components. Like Showa, their high-end motorcycle suspension is still wholly manufactured and developed in Japan. This is because the MX market is a flagship for both brands and certainly instils more company pride than looking at a new garbage truck, even if it is state of the art.

To confuse things even more so there is a third, smaller suspension manufacturer, Soqi (pronounced Sock-e). Originally part of the Showa group, Soqi is now under the Yamaha banner and is often confused with KYB. Soqi manufacture Ohlins’ units under licence in Japan, though for OEM fitment only. To understand how these relationships function, we need to look at Japanese culture and specifically their religion.

Perhaps as a result of its US ties, Kayaba reflects a more western business culture than Showa.

FUTURE TRENDS IN SUSPENSION BUSINESS

Active suspension anyone? We’ve been there in the ’80s, and it was dumped pretty quickly. It was not fun that when you left the jump’s face, the computer thought you needed more rebound damping because you’d stuffed the approach up, leaving you without the intended pre-jump lift. With good suspension, it’s all about predictability in the same way that fly-by-wire throttles have to be intuititve before they are acceptable on a motorcycle. Formula One currently uses a version of terrain-adjustable suspension but the old oil damper and coil spring fundamentals remain. Ducati has electronically adjustable clickers that were pioneered in World Superbikes but have since been banned. BMW and Ducati have used a similar system in some dual-sport bikes but it’s not exactly mainstream.

How about air-cells for springs? Fox tried it in the ’70s and Boge tried again with the BMW X-challenge. Light, cheap to make but not a crowd-pleaser. Mountain bike suspension makers seem to have got the air-cell to perform to a decent level but there’s a long way to go before it becomes the norm on your dirt bike. Fox has recently re-entered the market and if anyone knows how to make an air spring work, it’s Fox, but they’re still using coil springs.

Like the average waistline, fork tube diameter has slowly been creeping up. We raced on 31 and 33mm forks in the ’70s, 41 and 43mm in the late ’80s and ’90s. At the height of this trend we saw 50 and 52mm factory forks, but 48mm seems to be the magic number for flex, seal life and weight. When the tubes get too big they carry too much oil in the unsprung part of the fork.

For the next few years it will be refinement of existing designs, bigger shock bodies (with bigger oil capacites, bigger adjusters and new anti-friction coatings). Showa has released a new spin on an old concept in the shape of the 2011 KX250F forks – one leg to handle damping, the other just for the spring. The advantages are an equalisation of the weight of the calliper, meaning the front-end is better balanced and only one fork has to be disassembled for valving changes. But there are disadvantages – there’s not a wide range of differing springs available for them and there’s a degree of insensitivity in the valving. They work okay for your average rider but not for racing. Clearly a move to reduce costs rather than increase performance.

WP (the White Power name went the way of the Golliwog biscuits) has sadly pulled their aftermarket suspension business back to almost extinction, concentrating on OEM supply solely. Only Ohlins is offering some innovation with their TTX units. The through-rod zero displacement dampers that are being seen on cars have a great application in motorcycles, so it would be interesting to look at a design for a zero displacement fork cartridge. But there are design limitations for motorcycles due to space!

KYB vs. SHOWA

HONDA

For many years, the CR125 was KYBshod, the CR250 wore Showa and the CR500 just couldn’t make up its mind, swapping from Showa to Kayaba in 1995. In one of the most bizarre decisions – and a true reflection of the culture – the 1996 CR250 had KYB forks and a Showa shock. Honda went back to Showa forks with the new alloy frame in 1997 and has only returned to KYB on the ’09-on CRF450R. In somewhat of a tribute to KYB, the 2010 CRF250R has a Showa fork that could only be described as a carbon copy of the KYB 48mm unit. It seems they may have conceded defeat.

SUZUKI

Get ready for the biggest mix of KYB and Showa in history! The RM-Zs have used 47mm Showas since ’07, but the 250 wore KYBs in 2004-2006. The bestselling DR-Z400 runs Showa, while the RM250 has been KYB since ’02 – with an open-chamber fork – but they used a Showa twin-chamber before that. It was an unusual 49mm size. Then there were the ’96-’97 conventional twin-chamber Showas. The 49mm forks that Showa (USA) had left over in ’01 were the basis for the Pro Circuit ‘factory’ forks. Owner Mitch Payton saw a bunch of forks that were destined for the crusher, added billet axle feet and nitride coatings – instantly becoming factory kit.

KAWASAKI

Like Suzuki, there tends to be a lot of brand swapping – for price, performance or perhaps culture – no-one seems to know why (or they’re not saying). Kawasaki has traditionally used KYB, but the KX250F started to use Showa from ’06, while the KX450F remains KYB. The KX125 and 250 models have run KYB for all eternity. Kawasaki was the first company to use the 48mm fork in ’01 and it took till ’04 for Yamaha to catch-up.

YAMAHA

Going against the grain of the other Japanese brands, Yamaha uses KYB almost exclusively in all its motorcycles. When Honda was using the Showa twinchamber fork in ’97, it took until ’05 for KYB to release their own twin-chamber. The cylinder-valve fork Yamaha persisted with from ’96 to ’04 made a lot of suspension tuners busy. The new for ’05 forks only lasted one year but they got it right in ’06 as the basic design has been unchanged to date. And to confirm its great design and feel, Honda now uses it on the CRF450R.

 

Shock Linkage Maintenance

Is your rear suspension feeling sticky or stiff?

It could be your shock, but it's more likely to be your shock linkage. It can be fixed in under an hour with basic tools, without removing the swingarm or shock.
This article gives a foolproof, step-by-step guide to inspecting, diagnosing & greasing the relentlessly abused bearings in your bike’s swingarm linkage.
Courtesy of Transmoto Magazine.
 

Closed Vs Open Chamber Forks

Most modern bikes have either an open-chamber or closed-chamber design.

Click to download orginal article in Transmoto Magazine or scroll down to the bottom.
Courtesy of Transmoto Magazine.


THE REAL DIFFERENCE BETWEEN OPEN- AND CLOSED-CHAMBER FORKS

We explain the key differences between the two main fork designs used in modern-day dirt bikes, and how each affects performance, tuning and maintenance costs.

There’s a lot of talk these days about open- and closed-chamber forks, but what’s the real difference between the two? Is one better and, if so, where? Should we all be scrambling to fit a closed-chamber fork, or does an openchamber still have advantages?

For 20 years, conventional wisdom has said that open-chamber forks worked better in the bush, while closed-chamber forks were built for the demands of motocross and supercross. But if that’s the case, why have so many production enduro bikes recently been fitted with a closed-chamber fork? Off-road models from Husaberg and TM have sported a closed-chamber fork for a few years, while the 2012 Gas Gas range and Yamaha’s flagship new WR450F have both appeared with them for the first time.

Given this growing trend toward closed chamber forks (also known as “closed cartridge” or “twin-cartridge” forks), we asked suspension specialist, Teknik Motorsports’ Nick Dole, to offer an insight into each fork’s design elements, and their impact on performance, tuning options, durability and maintenance costs...

FORK EVOLUTION

We all know that forks contain springs and oil and a few other bits. Up until the mid-1980s, dirt bikes used fairly rudimentary damper-rod forks. But for more than 20 years since, a majority of dirt bikes have used an open-chamber cartridge fork. In 1996, a new closedchamber fork was released by Showa on the Suzuki RM250, and Honda followed suit on their 1997 CR250 with a 47mm twin-chamber Showa.

So how do we define the difference between the two major designs used in modern-day dirt bikes? For the sake of simplicity, we’ll use the term “open-chamber” when referring to a fork that runs one common oil and “closed-chamber” for a fork that uses two separate oils – one in the inner cartridge and another in the outer chamber.

OPEN-CHAMBER FORKS

This same basic design has been with us since the mid-1980s. A tube (cartridge) is sealed at both ends and when the fork compresses, a rod is plunged in the oil-filled tube, displacing oil. A valve assembly at the base of the cartridge meters the oil coming out of the cartridge when the fork is compressing. When the fork returns, or rebounds, the piston assembly attached to the end of the shaft (which has a similar arrangement of shims) produces a rebound damping force. The fork also contains a hydraulic bottoming device and, like all forks, uses oil capacity to manipulate the air spring, which affects the final onethird of the compression stroke (read up on Boyles Law for more detail).

As the oil is under no pressure (and little consideration was given to cavitation in the design and settings), it can become heavily aerated under hard use – and the inside of the fork resembles a milkshake! As the oil breaks down, a few things occur. First, this ‘cavitation’ affects the dampening character by weakening it significantly. Second, the fork loses its responsiveness as ‘hysteresis’ (the delay between an compression movement and a rebound movement) increases. And finally, the oil also loses its ‘lubricity’ (its capacity to lubricate) as the oil molecules are torn apart by the cavitation process.

PERFORMANCE

This design has been around for 30 years and won a lot of championships, so there is nothing wrong with an open-chamber cartridge fork. Earlier designs, however, lacked an understanding of the relationship between the base valve and the mid valve, causing them to feel harsh over roots and rocks and dive excessively under brakes. WP only started to produce well specificationed open-chamber forks after 2007. Yamaha’s poppet valve Kayaba fork (used on the WR-F) was famous for its deteriorating performance after not so many hours. Suzuki’s DR-Z400 and other trailbikes are still in the early-’90s in terms of their fork design.

MAINTENANCE

Every fork has seals and bushes and they all wear out after extended use. But the open-chamber fork is certainly a lot easier for the home mechanic to maintain and service. Yes, you still need to keep an eye on the shims – especially the mid valve’s shims for cupping against the face of the piston – and the top cartridge bush can wear, which releases dampening pressure. But, really, that’s about it. Sure, shims wear, and a complete cartridge disassembly and inspection is suggested at every service. Do that and change the oil every 50 hours, and they’ll be sweet. In general terms, they’re a pretty robust design.

TUNING

There is a huge scope to adjust the action and feel of an open-chamber cartridge fork. It’s very easy to swap out the springs as it doesn’t require you to remove the dampening cartridge first. In general, it’s easy to change preload settings, and the WP forks even have an external adjuster. No inner seals means no fear of damaging a lower cartridge seal during disassembly. There are plenty of aftermarket vendors who offer piston and valve kits to alter the fork’s dampening character. And remember, a well set-up pair of open-chamber forks will still out-perform a poorly set-up closed-chamber fork.

CLOSED-CHAMBER FORKS

The key difference with the design of a closed-chamber fork is that its cartridge is inverted, and a spring or bladder element is added to keep the oil under pressure. There is no air present in the inner chamber (or cartridge), but this alone does not eliminate cavitation.

Pressure springs are used in the Japanese-made forks, usually in the range of 1.6 to 2.2 kg/mm. WP forks, on the other hand, use a bladder system inflated to approximately 25psi to keep the oil under pressure. Marzocchi use a low-pressure bladder system, whereby the displacement of the compression piston assembly entering the cartridge inflates the bladder.

It’s not an oversimplification to say the damper assembly is simply inverted from an open cartridge fork, and there are interchangeable parts between open- and closed-chamber forks. The outer tubes are often the same in both fork types; as are major service items, such as seals, bushes and springs.

As the oil in the inner chamber is separate to the outer’s, different viscosities can be used, and the seals and bushes will benefit from using a heavier-grade oil. Varying the oil height still adjusts the air spring effect in the fork, but there is the added complexity because the spring is housed low in the fork leg. This creates a secondary dampening action when the upper spring seat is plunged into the oil. This occurs about halfway through the compression stroke.

PERFORMANCE

The sealed system creates both pros and cons. Oil under pressure alleviates the cavitation problems, so you get consistent performance, fast response times and low hysteresis. And riders all love the feeling of having no (or very little) un-damped section of the travel (or lag). But the fact that it’s sealed also causes some problems. There has to be a seal at the bottom and top of the cartridge – which are both sources of friction. If either seal leaks, the fork’s performance goes off very quickly. The pressurised system also causes an initial force that must be overcome before the fork starts moving. Pro riders won’t feel it, but riders who like a very plush fork, will.

MAINTENANCE

There is a tendency for owners to disassemble the outer legs of a closed system only, and to leave the inner chamber alone altogether. Considering the inner chamber only holds about 180ml of oil, that’s a false economy. The inner needs to be inspected for leaking seals, cracked free-pistons (which are common on Kayaba forks) and worn damper shafts. If a cartridge can’t hold pressure, you need to find out which seal is leaking and replace it immediately. If the inner is leaking, you won’t see any oil on the fork outer because it’s an internal leak. But you will notice the forks just don’t work how they ought to.

TUNING

As well as all the adjustment options of an open-chamber fork (springs, valving and piston kits), the cartridge spring pressure can also be altered in the Kayaba and Showa. Often the stock 1.9-2.1kg/mm springs will be swapped for softer 1.6-1.8 units if the fork is intended for off-road use and/or a lighter rider. The spring seats can also be changed to more restrictive types, giving a higher secondary dampening character for supercross; or very open, free-flowing versions for off-road use. One drawback is that you need to separate the fork legs and remove the cartridge just to change fork springs. It’s not the five-minute job it is for an open-chamber fork.

CLOSED VS OPEN CHAMBER FORKS: WHO USES WHAT?

While Showa got the jump in 1996/’97 with their 47/49mm closed-chamber fork, it has been Kayaba who’s set the bar for production fork performance in more recent years. Kayaba’s first closed-chamber attempt in 2005 had problems, but the 2006 fork was so good, it’s largely unchanged in 2012. Even Honda jumped on the Kayaba bandwagon in 2009 with the flagship of their motocross range: the muchrevamped CRF450R.

In 2010, it looked like Showa almost gave up. Honda’s CRF250R arrived with a 48mm Showa fork – with parts that were interchangeable with the Kayaba’s! All other 47mm Showa closed-chamber forks date back to the last major redesign in 2003. That said, it’s a good design and has created very few problems.

For 2012, after six years using a fork that was the weakest component of an otherwise excellent bike, Yamaha’s WR450F finally gave in and fitted an enduro-spec version of the Kayaba closed-cartridge fork their motocross range already ran.

The Marzocchi closed-chamber fork has been used on Husky, TM, and Gas Gas. It has moved over for the Kayaba fork on the Husqvarnas in 2012, but Gas Gas is sporting a new 48mm closed-chamber Marzocchi fork that looks like it’s a Kayabainspired design. As ‘inspired’ as the CRF250R’s Showa fork? Maybe.

As the closed-chamber fork is more expensive to produce, manufacturers are less inclined to fit it to every model. Showa addressed this with their SFF (Separate Function Fork), which runs damping in one leg and a spring in the other. While we all jeered at it in 2010, the SFF has proven its worth in competition and will surely be more widely used in future years, and the addition of an external spring preload adjuster on it is very helpful.

So why does KTM persevere with the open-chamber WP fork for its entire off-road range? Because the open-chamber fork still offers advantages for off-road riding. It’s lighter; it has spring preload adjustment; it has fewer seals and less sliding friction; it’s easier for the owner to service; and it allows faster spring changes. If only we could have a pressurised fork with the openchamber’s ease of maintenance. Too late; Ohlins did it in 2005 with a semipressurised system that used a floating seat on the cartridge. It works well, it’s cheap to make and adapts to existing designs. There must be a patent lurking around there somewhere!

CLOSED-CHAMBER FORKS APPEAR WHERE?

  • Kayaba 48mm – used on Yamaha’s YZ and YZ-F from 2005; Kawasaki’s KX450F from 2006; Honda’s CRF450R from 2009; Husky TCs from 2010; and Yamaha’s WR450F from 2012.
  • Showa 47mm – used on Honda’s CRs since 1997 and all CRFs; Suzuki’s RM-Zs from 2007; and Kawasaki’s KX250F from 2006.
  • WP 48mm – used on all KTM SX and SX-F models since 2007; Husaberg TC models from 2010, and TE models from 2011.
  • Marzocchi 48 or 50mm – used on Husqvarna’s TC and CR range from 2006 and 2009; Fantic’s TZ range from 2012; Gas Gas EC range from 2012; and TM’s entire off-road range from 2007.

In short, if your compression adjuster is on the top of your fork, it’s a closed-chamber fork.

 

Suspension Mods for your Budget

What kinds of modifications suit my budget? How can I get the best Bang for my Buck?

Do you know what modifications are available for your bike? Not many people do. And while some can spend big chasing the very pinnacle of performance, most of us have more modest funds.
Here are some options to make your suspension better, what difference they make, and what you can expect to pay for them.
Courtesy of Transmoto Magazine.
 

Gearing

Changing your bike's gearing can transform its personality overnight.

Click to download orginal article in Transmoto Magazine or scroll down to the bottom.
Courtesy of Transmoto Magazine.

On The Tools Tech Series:

ISSUE 1. SUSPENSION MODS How to get the most from your suspension budget.

ISSUE 2. GEARING -  Understanding sprocket combos and optimising gear ratios.

ISSUE 3. CARBS & EFI - Clever tuning tips to get your air/fuel ratio right.

ISSUE 4. NUTS & BOLTS - How to remove broken bolts & get the right torque settings.


GEARING AND HOW TO MAKE IT WORK FOR YOU

The right gearing can transform the way your bike drives and handles. We take the mystique out of the sprocket math to help you tailor your ride.

A dirt bike’s chain and sprockets operate in a nasty, open-to-the-elements environment, and yet we’d be lost without them. Over the years, we’ve tried shaft-drives, hydraulics and belt-drives, but we keep coming back to the humble roller drive-chain invented by a Greek around 300BC. Why? Because they suit dirt bikes perfectly. They’re tough, simple, light, create minimal power loss and they’re cheap.

Sure, shaft-drives are quieter and require far less maintenance, but they’re heavy in an unsprung mass kind of way, plus they make gearing changes difficult. And while belt-drives are quieter and more efficient than shafts, sand, rocks and mud make very short work of their lifespan.

So what makes this world of chains and sprockets tick? How can you alter you bike’s power and handling characteristics with different gearing combinations? And how can gearing changes make life in the saddle more enjoyable? You’re a few toothy pages away from enlightenment.

 

GEARING GLOSSARY

Countershaft sprocket – the countershaft delivers the power out of the gearbox, and the front/drive/countershaft sprocket is attached to it.

Cush-drive (hub) – a rear hub designed to have a carrier mounted to it so the engine’s drive or torque pulsations are dampened by large rubber blocks. This saves the gearbox from shock-loading. There are also aftermarket cush sprockets available.

Low-noise sprocket – has a ring of rubber bonded to it so the chain runs on it. They’re common on trailbikes, and can be replaced with a non-rubber type with accompanying noise.

Gear up/taller/higher gearing – the drive ratio is numerically decreased by fitting a smaller rear sprocket and/or a larger front sprocket.

Gear down/shorter/lower gearing – the drive ratio is numerically increased by fitting a larger rear sprocket and/or a smaller front sprocket.

Loctite – proprietary name (eponym) for an anaerobic thread-locking agent. That is, it hardens in the absence of air.

Final drive – chain and sprockets in combination as a gearing set.

 

WHY IS GEARING IS IMPORTANT…

Why do we have a gearbox at all? Why not just run in a single gear? After all, gear changes cost you time on the track, right? Well, if we were punting a go-kart running around a flat course, not changing gears is a practical way to go faster. Unlike go-karts, dirt bikes need to start from a standstill, climb hills and have a broad speed range. This is why many enduro bikes have six-speed gearboxes, why most motocross bikes have five-speed boxes, and why bigbore machines with oodles of torque can get away with four-speed transmissions.

So, for a given gearbox, how do we tailor the final drive to suit us? That all depends on where you use the bike and how you like to ride it. Do you ride to work and rev the engine hard at 110km/h? Gearing can solve that. Do you struggle to get up big hills? Gearing can help there, too.

MX/SX GEARING

How many times do you change gears around the average motocross or supercross lap? Twenty, thirty times? When you shift, you’re not accelerating; you’re revving the engine near peak horsepower and shifting back into an RPM band with peak torque to start the acceleration curve again. What happens if you miss a shift or hit a false neutral? Do you let a rider by as you lose forward drive or case a jump and crash? By thinking about your shift points and whether you’re in the right portion of the power curve through the fastest corner on the track – the corner we traditionally gear for – substantial improvements in lap times can be made.

When you drive out of a corner, are you usually in second gear and struggling to grab third on the exit? Is third too tall for the engine to pull through several corners and you find you’re using a lot of clutch to keep it in the meat of the power? Could you gear up and use second until the bike is straight and not bouncing off the limiter, or gear down so you can comfortably grab third earlier for a smoother drive? Is there a long straight that you are grabbing a gear on towards the end and wasting time? Are you forced to upshift dangerously close to the upramp of a big jump? These are the key questions to think about to ensure your gearing is not unnecessarily costing you precious seconds around each lap. With many different corners on any given track, there will ultimately be some sort of compromise. But changing one or two teeth on the rear sprocket will usually be enough to sort most issues.

When changing sprockets and making corresponding changes to the rear axle position, also consider the implications of the effective change in swingarm length. Generally speaking, a longer swingarm (or wheelbase) creates a more stable chassis that is less inclined to wheelstand. A shorter swingarm allows the bike to turn quicker, but it also creates a firmer feel from the rear suspension because of the decreased leverage.

ENDURO GEARING

Not many off-road riders count gears; we’re usually too busy with fistfuls of throttle, dodging trees and bashing away at the gear lever to notice. So next time you ride, take some time to think about it. How often do you use first gear? Is the gap from first to second too big? Can you make a gearing change to effectively create a gear between first and second, or to never use first at all?

New-model four-stroke enduro bikes generally have a broad spread of useable power and wide-ratio gearboxes, which makes final gearing less critical. But that doesn’t mean gearing changes can’t reap benefits. If you’re having trouble taming a two-stroke for the bush, for instance, taller gearing can help smooth the power delivery. And finding the right gear for tight singletrack can be the difference between flowing through the trees and kissing one on a missed shift.

Bear in mind what you do at the bottomend will affect the top. If you shorten the gearing for more snap at slow speeds, you will lose some top-speed. Carefully consider the terrain type, and aim for a final gearing combination that offers you the most versatility.

TRAIL/DESERT GEARING

Desert is easy – run the tallest gearing your engine can pull. Machine the rear hub down if required! Then, let natural fear regulate your decision and put a few teeth back on the rear. The Honda CR500s that dominated the Finke Desert Race in the 1990s ran a 15/36 final drive, while the newgen CRF450s run a 15/44 or 14/42 gearing combo at Finke – much taller than the bike’s standard 13/48 motocross gearing. Trailriders can use the easy-to-swap nature of the countershaft sprocket to have ride-to-work road gearing and off-road gearing. One tooth will usually do it with no chain length changes needed. For example, you could use a 13-tooth in the bush and 14- or 15-tooth for the road, with that one tooth transforming the bike for each application.

 

WHY CHANGE GEARING?

Below is a simple chart for gearing. The ratio is simply the rear sprocket divided by the countershaft. For example, if your bike is running a fairly common 14/48 combination, that will give you 3.43. Notice that 13/45 or 15/52 will give a similar result at 3.46 and 3.47, respectively, just slightly shorter.

Numerically higher numbers will make the engine turn faster for a given speed, giving faster take-off and a lower top-speed. Higher numbers will give a slower take-off and a higher top-speed. Note that shortening the gearing will effectively close the gearbox ratios up, giving a closer-ratio feel.

COUNTERSHAFT SPROCKET

TEETH

12

13

14

15

16

17

39

3.25

3.00

2.79

2.60

2.44

2.29

40

3.33

3.08

2.86

2.67

2.50

2.35

41

3.42

3.15

2.93

2.73

2.56

2.41

42

3.50

3.23

3.00

2.80

2.63

2.47

43

3.58

3.31

3.07

2.87

2.69

2.53

44

3.67

3.38

3.14

2.93

2.75

2.59

45

3.75

3.46

3.21

3.00

2.81

2.65

46

3.83

3.54

3.29

3.07

2.88

2.71

47

3.92

3.62

3.36

3.13

2.94

2.76

48

4.00

3.69

3.43

3.20

3.00

2.82

49

4.08

3.77

3.50

3.27

3.06

2.88

50

4.17

3.85

3.57

3.33

3.13

2.94

51

4.25

3.92

3.64

3.40

3.19

3.00

52

4.33

4.00

3.71

3.47

3.25

3.06

HOW GEARING AFFECTS…

MOTOR

Back in the pre power-valve days, where 125s produced 30hp between 10,400 rpm and 10,500rpm and 15hp either side of it, gearing was critical for keeping an engine ‘on the pipe’. These days, user-friendly twostrokes and new-generation four-strokes have made life easier with their flatter and more forgiving torque curves. But we still have the same objective: to utilise the engine’s torque to pull us around. Underrevving (labouring) and over-revving an engine have never been ways to extract its best. So whether you want some more snap off the bottom, less gear changes per lap, or a higher top-speed, gearing changes can achieve this for you.

SUSPENSION

The most obvious change gearing makes to suspension is swingarm length. With the rear axle back as far as it’ll go, the swingarm is at its longest and has the most leverage over the shock. This effectively makes the shock softer. Moving the wheel forwardreduces the swingarm’s leverage, and the shock becomes stiffer.

Chain torque is another matter and could easily fill up a book with formulas and algebra. Put simply, chain torque occurs because the countershaft sprocket is in front of the swingam pivot on the majority of motorcycles. Chain torque opposes the downward force the rider puts on the rear suspension. Don’t believe it? Put your front wheel against a tree and let the clutch out. The rear of the bike rises. This lift helps you to clear obstacles in the same way prejumping does.

SPROCKETS

Steel or alloy? A steel/alloy combo? Self cleaning? What’s best? In general terms, if you are all about saving weight, buy alloy. Note that there are many varieties of alloy, and a quality English-brand sprocket will outlast a cheap no-name brand many times over. There are a few self-cleaning types around and everyone has their own miraculous cure. Personally, I’m more interested in the quality of the aluminium. However, even a cheap steel sprocket will outlast an alloy unit, so trailriders are best to go with steel. Enduro guys will have to decide where they sit on the weight versus wear trade-off, and perhaps go for one of the steel-toothed alloy sprockets or a lightweight steel unit.

Quality sprockets can cost more than $100 each, so building a collection for gearing choices can start to blow the parts budget out. Be sure what you want gearing-wise before splashing out. The best thing about a collection is that all major manufacturers have not changed their sprocket bolt-patterns in years.

So how do you know when your sprocket has had the sword? You’ll see most of the wear on the drive-side. The teeth will start to hook over, before the hooks themselves begin to break clean off. The stumpy little teeth that remain will soon let the chain spin and ruin your day. As a rule, replace chain and sprockets as a set, as a worn chain will quickly ruin new sprockets and vice-versa. Once you see hooking, it’s game over for the sprocket. Although not immediately obvious, sprocket wear costs power. Nothing absorbs less power than a brand new sprocket, and once your sprocket teeth begin to hook, it takes more energy to drive them.

Keep in mind that the fewer teeth on the countershaft sprocket will accelerate wear on both the sprocket and the chain buffer on top of the swingarm, as it will have more sliding friction on it. So with your gearing choices, try to keep the countershaft size up to 13 or above as a 12-tooth wears too fast to keep in check. Note also that some engine cases or case savers don’t allow the fitment of a 15-tooth sprocket unless modified.

The chain guide often limits rear sprocket size. A 52-tooth unit is normally about as big as you can go without mods to the guide. Always inspect sprockets for damage as it is possible to bend the rears, most likely when the chain guide is bent with a rock.

DRIVE CHAINS

Thirty years ago, drive chains were a curse. They stretched faster than you could adjust them, and broke so often that you were wise to carry a few spare links, spare section of chain, a chain breaker and a countershaft sprocket just in case. The advent of the O-ring chain in the ’80s changed all that. The O-rings fit into the gap between the rollers and the links and help trap the lubricant in the pins. Mind you, the chains still need lubricating on the rollers. The early O-ring chains were bulky affairs that sapped power, but the reliability was worth it. As we got into the ’90s, the O-rings were replaced by X-rings. The X refers to the cross-sectional shape of the ring, much like an O is the cross-section. The advantage of the X is not being crushed between the rollers, as the X has two contact points per face. It also meant the sealing lasted longer as the O-rings did wear out.

An unexpected benefit was that O- and X-ring chains ran cooler due to reduced friction. On high-powered machines, this meant the X-ring chains absorbed less power than a conventional chain. We now have a few manufacturers making sealed chains for low power applications, like 250Fs, in the form of U-rings and T-rings, all with seals that bear some resemblance to the letter that defines them. Only in high-level competition is a non-sealed chain still worth some power advantage. But as the non-sealed chain wears, it absorbs more power as heat loss, and the advantage disappears.

Joining links can still cause headaches. Unless you have a good reason to remove the chain frequently for cleaning, I’d suggest a rivet link is the best insurance. They take a little extra effort to put on, but there’s little need to break modern chains again until they’re worn and ready to be replaced.

As for chain quality, let price be your guide. The O-ring chain you buy for $89 is a nasty piece of power-robbing, sprocketwearing work compared to the lightweight long-lasting joy of a $180 X-ring. Given the choice, always buy a gold chain. They are usually only 10 to 15 bucks more, but the plating prevents rust and makes cleaning easier as a result.

GO ON, CHANGE YOUR GEARING!

Swapping sprockets is a simple enough job with few basic tools. The most difficult part is removing the countershaft sprocket nut, and avoiding losing skin on the rear sprocket.

There are two common ways to remove the countershaft nut. The old method was to have an assistant stand on the rear brake while you used a long bar and socket. The folding tab needs to be knocked back with a cold chisel and if there is Loctite, some heating will help to make the nut shift. You need to stand on the rear brake quite hard to make this work. The advent of cheap air compressors and impact (rattle) guns from hardware stores means there is now an easier method. Leave the chain on and have an assistant stand on the top of the chain to keep it tight while you loosen the nut. It’s only the shock of the hammering action that loosens the nut. So by keeping the chain taught, all of the impact is acting on the nut. Don’t be tempted to put the machine in gear as the rotating hammering action will be lost on the gearbox gears, not on the nut. And using a section of chain curled up and jammed into the cases is also a good way to break a case.

While the rear wheel is out, remove the chain adjusters that run into the swingarm and apply some anti-seize. There’s no telling when they will be out again.

TOOLS

If you have an Allen key set, ring spanner, Loctite and a 24, 27 or 30mm socket to suit your rear axle nut and countershaft nut, then there’s no excuse for you not to experiment with different gearing combos.

DIY GEARING TIPS…

  • Sprocket bolts don’t take kindly to being over tightened, even a small amount. Put a set of high-quality replacements on your shopping list when you buy a sprocket.
  • Loose sprocket bolts will destroy a rear hub faster than you know how to spend $400-$800 on a replacement. It doesn’t take long to check the bolts before each ride, so get into the habit of it.
  • Some type of mechanical self-locking nut is a must for rear sprockets. Be aware that self-locking nuts do wear out after two or three tightenings.
  • For the few bikes that still use a circlip to retain the countershaft sprocket, a bead of silicone will provide cheap insurance against the clip being flicked off.
  • Replace the folding tab that mechanically locks the countershaft nut rather than relying solely on Loctite. It’s such a critical fastener, overkill does not exist here.
  • Use a long ring-spanner to loosen the sprocket bolts’ nuts before you start turning the Allenhead. The Allen-head is only for holding and loosening, not tightening.
  • Look for blackening around the bolt heads during your post-ride wash. If you can see it, chances are the bolts are loose and fretting.
  • The sidewall height of a tyre will affect gearing. A 110/80-19 will have a smaller rolling diameter than a 110/90-19, thus shortening the gearing. Conversely, the 90-profile is taller and will require you to gear up to counteract its effect.


 

Air / Fuel Ratios

Is your engine running properly? Got a flat spot in power? Is it lean or rich?

Click to download original article in Transmoto Magazine or scroll down to the bottom.
Courtesy of Transmoto Magazine.

On The Tools Tech Series:

ISSUE 1. SUSPENSION MODS How to get the most from your suspension budget.

ISSUE 2. GEARINGUnderstanding sprocket combos and optimising gear ratios.

ISSUE 3. CARBS & EFI - Clever tuning tips to get your air/fuel ratio right.

ISSUE 4. NUTS & BOLTS - How to remove broken bolts & get the right torque settings.


DIAGNOSTIC TOOLS AND AIR/FUEL SOLUTIONS FOR ENGINES FED VIA CARB OR EFI

Arm yourself with diagnostic skills so you can feed your motor right.

Both two- and four-stroke engines remain fundamentally unchanged since the late 1800s. Sure, they’ve been refined, made from new materials, and their performance developed massively. But they still need a means to get the fuel into the engine, and the carburetor has fulfilled this role, working under a basic atmospheric principle. Fuel injection then arrived in the 1920s and has largely overtaken carburetors in all but one field – dirt bikes. Until now!

So are the fuelling needs of a carburetor engine and an injected engine different? No! The engine has no idea what’s feeding it. All it knows is that its ideal air/fuel ratio is 14.7 grams of air to 1 gram of fuel. This varies from 6:1 for a cold start to 17:1 for super-lean burn economy, but generally, it’s accepted that a ratio in the vicinity 12:1 makes the best power.

So what happens if the engine doesn’t get what it needs? A flat spot (or bog) is the result of a mildly rich or lean condition, which is enough to put you over the bars when crossing a log or casing a double. An excessively rich mixture will wash oil off the bore, dilute the oil, and increase engine wear. A too lean air/fuel ratio is more dramatic as it causes the piston crown temperature to rise, which usually means a piston failure or a seizure is imminent.

In any case, the consequences can be costly, so it pays to get you engine’s diet right. The following pages give you the diagnostic tools to proscribe air/fuel solutions, whether your engine’s fed via carb or EFI.

HOW A CARBURETOR WORKS

Carburetors all work on the same principles. A venturi, or a narrowing of the carburetor bore, creates a low-pressure zone, allowing fuel to be ‘pushed’ out of the jets by atmospheric pressure acting on the fuel in the bowl. The most fundamental aspect of carburetors is they are dependant on throttle position, not RpM. So wherever you hold the throttle is controlling the jet that has the most influence.

Carbs come in lots of configurations to suit specific models. In competition-orientated dirt bikes, the slide-type carb is the most popular for its high airflow and power output, while the butterflytype CV carbs are trailbike low-tech.

The two most prolific carby manufacturers are Japanese: Mikuni and Keihin. Of the two, Keihin controls the four-stroke scene on all brands with their FCR (Flat CR). It’s a development from a mid ’90s superbike carb that has its roots in the 1980s.

ACCELERATOR PUMP

Two-strokes don’t need ’em. Four-strokes don’t either if you roll the throttle on. As the four-stroke has come back as our preferred engine, some enrichening device to overcome the low airspeed and resulting lean condition (bog) was needed. A mechanical pump, linked to the throttle, injects a short shot of fuel while the airspeed picks up as revs rises. The FCR pump system has its own bleed-back jet to control duration.

FLOATS

The fuel height in the bowl needs to be controlled so floats are use together with a needle and seat to regulate flow. Got fuel pouring our of an overflow tube? Either the float level is too high or there is dirt in the seat. A quick tap with a screwdriver handle usually works the dirt loose.

NEEDLE & JET

Mikuni carbs have a needle jet you can swap out as another tunable part. Keihins do it with the straight portion of the needle. There are between five and seven needle clips positions to raise (richen) and lower (lean) the mixture. See the diagrams (left).

COLD-START

Chokes got their name from restricting the intake of the carb with a butterfly, exaggerating the pressure drop and richening the mixture – essential for cold starting and running. More modern systems are a bypass, sometimes with a separate jet and a means to lift the idle speed while the choke is on. The hardest function for an engine to perform is idling!

PILOT JET

Controls the idle and low revs, usually up to one-quarter throttle openings. It’s usually trimmed by a fuel screw or airscrew. To identify which, you have look at where the screw is. If it’s before the carburetor slide, it’s usually an airscrew, so turning it in (clockwise) shuts down the air bleed to create a richer condition. If it’s after the slide, and it’s a fuel screw, so turning it out (anticlockwise) richens the mixture.

MAINJET

In reality, the mainjet is the last jet you worry about getting right. Its influence starts from throttle openings as low as half, but the pilot, mixture screw and needle need to be right before you get there. Mainjet tuning is the most interesting as it will involve some high-speed runs, often timed between fixed points the find the optimum.

HOW EFI WORKS

The ECU (Electronic Control Unit) gets a crank signal from the trigger, usually in the left sidecover under the flywheel. From this, it knows what the engine RpM is and where the crank is over 360 degrees, as there are 12-18 “teeth” on the reluctor (the pick-up ring for the trigger). The highpressure fuel-pump in the tank is driven on start-up by a capacitor (like a battery, but smaller). The ECU gets signals from all the sensors (inputs) and looks at the loaded map for the appropriate outputs, opening the injectors, turning the fuel pump on. The length of time the injectors are open for is “pulse width”. There can be single, double or multiple pulses for one engine revolution.

ECU

The “brains” of the whole system is the ECU. All of the inputs from sensors such as engine RPM and throttle position come in and are plotted on 3D mapping to deliver outputs for quantity of fuel-injected spark timing, and when to turn the fuel pump on and off.

SENSORS

The main sensors are crank speed and air volume or pressure (Manifold Absolute Pressure, MAP). With these two inputs, the engine will run. Throttle position, water temp, air temp, crank position, cam position and exhaust oxygen content all add to the accuracy of the fuel delivered.

THROTTLE BUTTERFLY

Unlike our high-performance Keihin FCR’s slide, throttle position on current EFI systems is controlled with a butterfly, just like your car. It’s a bit down on airflow for a given bore size compared to a slide, so we are seeing some big throttle bodies like the 50mm unit on Honda’s CRF250R.

FUEL PUMP

A constant supply of high-pressure fuel to the injector is critical for accurate fuel metering. Dirt bikes are hard on the fuel pump. Dirt and water can enter the pump through the tank or jump landings can jolt it. If the fuel pump fails, the whole show stops. So it pays to be careful when refuelling.

AIR/FUEL DIAGNOSTICS

There is an old saying: “lean is rich and rich is lean”. Even the best can be fooled so it’s important to listen carefully to your engine before you make a change. However, a change will tell you quickly which way to go. Before you start pulling carburetor apart or reaching for the laptop, fit a new sparkplug, fresh fuel and air cleaner and be sure the engine is in sound mechanical condition.

Typically, a regular rhythmical misfire is richness. The engine feels soft, the exhaust note is mellow. Leanness is characterised by an irregular misfire, an overly sharp throttle response (even after an initial hesitation) and induction noise. A quick way to check is to pull the choke on; the extra fuel will either help the problem or make it worse, so you know where to go.

Sparkplugs will still tell you a bit of the story, but be aware modern fuels all make the plugs look dark.

The different settings that are loaded into an ECU are called maps because they resemble a 3D terrain map as the throttle position and RpM are plotted on a table. Not to be confused with the MAp sensor!

PROBLEM

SOLUTION – CARBY

SOLUTION – EFI

Won’t start – no fuel

Fuel tap blocked, needle and seat stuck

Fuel pump has no signal, ECU won’t start pump, dead pump

Idles, but won’t take throttle

Pilot jet blocked

TPS not working

Poor cold starting

Too lean, pump the throttle 3 times for FCR

Coolant or air temp sensor fault

Misses at part throttle constant

Straight section of the needle

Blocked air filter or remap

Bogs on up-ramps

Pump timing out or pump too strong/weak

Re-map, low fuel pressure, sensor unplugged

Won’t rev out

Mainjet too big or small

Re-map, low fuel pressure, blocked injector

Leaks fuel from overflows

Needle and seat stuck

Fuel line leak

Erratic running, irregular misfire at idle

Too lean on pilot/mixture screw.

Air leak, blocked injector

Misses at part throttle constant

Straight section of the needle

Re-map

 

COMPARATIVE COSTS: CARBURETOR VS EFI

The real bonus of EFI tuning is not pulling carburetors apart on the side of the track. All the factory programming tools will allow a range of tuning, generally 10-30% richer and leaner with not a lot of scope to advance ignition timing into a detonation zone. The tools are all designed to be used by a capable person who has carb tuning experience as the symptoms of EFI mixture are the same as carby’s. Some of the tools will allow a selection of maps to be made in the comfort of your shed, then tested on the track as you upload and download maps.

Of all the programming tools, the Yamaha tool is the most accessible at $399. It does what you need with a few more bells and whistles. The Vortex X10 ECU is worth a mention too at $799. It has 10 pre-loaded maps and a low/mid/highrange adjustment to make trackside tuning a screwdriver operation.

The danger with EFI diagnosis is replacing the wrong part. If the fault code says replace the ECU and you do, but the fault code persists, there is no returns on electrical parts for any brand, regardless of what the fault code said. This is where substituting parts from the same model can be helpful as long as you’re super-careful with the plugs and terminals.

The difficulty with EFI at present is that many dealers don’t have the tuning tools and of those who do, how many of them will be able to offer you an alternative map for your new pipe? There is no aftermarket programming tool that will do all the models, so you will have to look hard for a workshop that has the brand-specific tuning tool for your model and has a dyno or a test facility or have access to good tested maps from the distributors. Experience with power Commanders (Dyno Jet) on road bikes that download a map from a US-based site is hit and miss as the fuels are different between the countries. Luckily, the mapping on the MX bikes so far has been very good but like all things, there is always room for improvement.

OPERATION

CARB

EFI

Re-jet on dyno

$250-$350

$250-$350

Diagnose poor running condition or no start.

$100 will cover most diagnosis.

Find a dealer with the tool, pray it’s a simple sensor fault and not a damaged wiring harness. Pay per hour. Don’t complain, as it’s not that easy.

 

CARBURETOR PROs & CONs

CARB PROs

  • Everyone knows what it is and most mechanics will pull a carburetor apart.
  • Light, robust and relatively easy to tune with a handful of jets.
  • Because they are driven by airflow, they are able to auto adjust for blocked air filters, aftermarket pipes and engine wear.
  • That damn FCR is very good!

CARB CONs

  • Modern frames have meant it’s an ordeal to remove the carb to re-jet.
  • FCRs are hard to understand for most people with so many circuits, so re-jetting is daunting.
  • People pull them apart and don’t always get them back together correctly.
  • Jets are expensive when you start to have a collection, and you can easily spend a couple of hundred bucks on brass. It’s easy to see carbys as old hat when the industry is driven by that shiny new thing.

EFI PROs & CONs

EFI PROs

  • Complete confidence that your engine won’t bog on an up-ramp or anywhere else.
  • Easy to live with when it’s working.
  • EFI opens up a whole new world of aftermarket ECUs and notebooks for the tuner in us all.
  • No more flooding when you stall it, no leaking fuel in the van as you drive, no vent hoses to get blocked up.
  • Ignition and fuel in one neat box.

EFI CONs

  • Dirt. It gets into everything.
  • The plugs on an EFI harness are very susceptible to dirt and mud.
  • Got an EFI problem you just can’t fix? Replace the wiring harness as damaged plugs will cause ECU fault codes to be logged.
  • EFI is difficult to diagnose when it goes wrong. A flashing idiot light is about all you get without the tuning device.
  • EFI can’t compensate for engine wear or even a blocked air cleaner like a carby can.

EFI TOOLS

What tuning tools available for Honda, Kawi, Suzi, Yami, KTM, Gas Gas and Husky? The following table summaries their features.

 

AVAILABLE TO PUBLIC

USER DEFINEABLE FUEL MAPPING

USER DEFINEABLE IGNITION MAPPING>

BASIC DATA LOGGING

STAND ALONE?

FAULT DIAGNOSIS

MULTIPLE MODELS

GOOD & BAD POINTS

FACTORY TEAM RACE BIKE ECU

COST

HONDA

Yes

Yes

Yes

No

Can interrogate ECU

No

12V battery required

Light in

kill-switch code.

SCS connector

Yes

Expensive

But it does all models

and years with

software upgrades

Vortex

$925 box

($120 software

upgrades)

KAWASAKI

Yes

Yes

Yes

Yes

Yes

Yes

Yes

TBA

Vortex

$770 ($130

software upgrades

SUZUKI

Yes

Yoshi box

Yes

Yes

No

Yes

F1 light OEM

250/450

Expensive.

Different unit for

old & new 450

Vortex

$899

YAMAHA

Yes

Yes

Yes

Yes

Can interrogate ECU

Yes

Battery

Yes

Live data

No

Heavy on batteries.

Well priced.

Boyd – Stock

Marmont – Vortex

$399

KTM

Yes

Yes

Yes

Yes

No

Yes

Yes

No info yet

Stock

$950

GAS GAS

Yes

No

No

No

No

Yes

Yes

Gas Gas maps only

N/A

$860

HUS New tool coming for ‘11 MX.

No

(for ’08-’10,

dealer only)

Yes

No

No

Yes

Yes

250/450 and

BMW in ’11

Apparently like the

Yamaha tool

N/A.

(Carby on Ando’s)

TBA

 

THE FUTURE OF EFI

EFI is here for good. Carbys will drift into obsolescence or the dual sport market at least. The two-stroke may well be the last bastion of brass until KTM releases the injected 300 disguised as a Husaberg. EFI’s biggest downfall at present is dirt. It’s the reason we didn’t get injection for so long. The dirt bike is about as hostile as operating environments get for electronics. As plugs need to come apart for routine servicing, every unit will – no matter how well sealed – get dirt in it eventually. This is where the rot starts. Those little terminals get spread open fractionally and loose electrical content, and it’s over. Tape the connectors up while the bike is new and re-tape them regularly. If a certain factory race team didn’t know their air temp sensor was unplugged (they forgot to connect it), then at least taping will make you check your connections.

Hopefully the future will see a throttle body with and ECU and MAp sensor integrated into it. Until then, the wiring harness will continue to be a problem.

What will these EFI bikes be like in 10 years? The sensors generally last, as do the injectors. Pumps fail, as do harnesses and plugs.

Of the aftermarket companies offering ECUs, Vortex must be doing something right. The Honda, Suzuki, Kawasaki and Yamaha factory teams all use their ECU, as do Geico and a few others in the USA.

The SSB (Simon Smart Body) is also interesting, using a slide throttle body to replace the butterfly. It’s sid to deliver impressive power gains, but with a reported 63hp from Cody Cooper’s factory RM-Z450 this year, do we want more power?

 

Changing Shock Springs

They are full of potential energy, and if you aren't careful with how you remove them, can be shockingly powerful.

Click to download original article in Transmoto Magazine or scroll down to the bottom.
Courtesy of Transmoto Magazine.


Because they are always being pushed around by heavy bikes and riders, they need to be. Keep that in mind the next time you buy a bike; springs are matched to weight, and you may not be the weight they had in mind when designing the motorcycle. It might be time to change them.
Courtesy of Transmoto Magazine.
 


HOW TO CHANGE YOUR SHOCK’S SPRING AND DIAL IT FOR YOUR WEIGHT AND RIDING STYLE

Manufacturers make a decision about what spring-rate to run on their bikes, based on their best guess about who the ‘average buyer’ of that model will be. For example, a 250cc trailbike is more likely to be ridden by a lighter, slower rider than a 450cc motocross bike and, as a result, its stock spring will usually be softer.

Sometimes, the standard spring happens to be perfect. But often, heavier or faster riders will require a heavier rate, and vice-versa. If you’re unsure whether you’re running the right spring, speak to a suspension expert – get some professional advice and buy one that’s correct for you. While you might be tempted to stretch the truth about your size or style, it will only tend to backfire on you later. With the correct spring in hand, the process of changing springs isn’t particularly difficult.

Teknik Motorsport’s Nick Dole explains the process.


DIY WORKSHOP

IN THE SERIES…

MAY ISSUE 31. COOLING SYSTEM - Nothing watered down here.

JUN ISSUE 32. HEAD BEARINGS - No more shaking like Elvis.

AUG ISSUE 34. MUFFLER REPACKING - Because stealth is better.

SEPT ISSUE 35. VALVE ADJUSTMENT - Keep that thumper pumping.

OCT ISSUE 36. 4T PISTON CHANGE - Four-strokes get tired, too.

NOV ISSUE 37. TIMING CHAIN - Change it the right way.

DEC ISSUE 38. CHANGING SHOCK SPRINGS - Get that bounce dialled.


TOOLS YOU’LL NEED

  • Spring compressor
  • Pre-load ring spanner
  • Socket set or T-bars
  • Copper anti-seize
  • Flat-blade screwdriver
  • Hammer
  • Punch

WHAT IT’LL COST YA

  • Labour: 1 hour
  • Shock Spring: Up to $250

 

1. REMOVE THE SHOCK

To replace the spring, the rear shock needs to be removed from your bike. This process varies from bike to bike, but you’ll typically need to remove the seat, rear section of your exhaust, airbox cover and sometimes part of your rear subframe. Remove the top and bottom shock bolts – almost all shock bolts have captive heads, meaning you can simply use a T-bar to remove the nut. Then, gently hold up the swingarm, push the bolts out and the shock will come free.

2. COMPRESS THE SPRING

The best way to remove the spring is to use a spring compressor – a special tool designed to compress the shock – which allows you to remove the spring retainer. If you don’t have one, and you haven’t adjusted the spring pre-load rings in a while, try and beg, borrow or steal one from a mate to avoid the possibility of ruining your shock’s thread. With a spring compressor in hand, simply place the shock in the compressor with the spring seat nestled in the hole, then use the jack to compress the spring.

3. LOOSEN THE PRE-LOAD RINGS

If you don’t have access to a spring compressor, then you’ll need to do it the traditional way – with a hammer and punch. Before you begin, give the shock thread and pre-load rings a thorough clean and spray the whole area with penetrant. That should prevent the rings binding. Next, with the shock held in a vice, use a hammer and punch to loosen the top pre-load ring and wind it up as far as possible. Loosen the bottom pre-load ring by turning the spring and pre-load ring together. If the rings bind, stop what you’re doing and take it to a bike shop – a buggered shock thread will cost you big bucks.

4. REMOVE THE SPRING RETAINER

With either the spring compressed in the spring compressor – or having wound out the pre-load rings as per Step 3 – the spring should be loose with an inch or so of play. Use a screwdriver to push the bumpstop up the shock shaft, allowing the spring retainer, rubber cup and spring seat to move freely. KYB and Showa shocks have a slot in the spring retainer that allows it to be removed from the shock shaft, while KTM’s WP shocks have a removable collar. This will allow the spring and spring seat to be pulled off the shock.

5. REPLACE THE SPRING

With the spring retainer or collar removed, the spring and spring seat will slide over the bottom-end of the shock freely. The new spring can be simply slid into position. On KYB shocks, the spring is a different diameter at each end; so be sure to measure both ends of the spring and orient the smaller end upward. While the spring is off, inspect the shock shaft according to Step 7 (overleaf ). If you’re working on a motocross bike with aluminium pre-load rings, consider replacing them with steel units as they’re less likely to bind on the shock thread.

6. CHECK THE LOWER SHOCK BEARING

The lower shock bearing – especially on bikes with linkages – always cops a beating, thanks to being regularly drenched with water. While the shock is off the bike, take the time to inspect and regrease the bearing. Use penetrant to clean off any old oily grease or surface rust, and run over the inner collar with some fine sandpaper if it has any marks on it. Then repack the bearing with grease, making sure to fill around all of the bearing’s needles.

7. INSPECT THE SHOCK’S SHAFT

While the spring is off the shock, slide the rubber bump-stop all the way up the shaft and rotate it, looking for any deep marks or scratches. Then pull the bump-stop down and repeat the process on the other end of the shaft. If there are any serious marks – especially at the top-end of the stroke, which sees more action – you may need to get it re-chromed or replaced. Grit can cause wear if it is lodged between the bump-stop and the shaft. You should pull the bump-stop up every couple of times you wash your bike, and hit the shaft with the hose.

8. REINSTALL THE SPRING RETAINER

With the top and bottom pre-load rings wound up high as possible, reinstall the spring seat making sure to put it on the right way up. Then, slide the spring retainer over the shaft – on a KYB or Showa shock – or replace the collar on a WP unit. The bump stop can then be returned to its normal position. When you tighten the pre-load rings in the next step, make sure the spring retainer, spring seat and rubber bump cap are all correctly seated.

9. SET THE PRE-LOAD RINGS

With the whole unit back together, apply a liberal dose of copper anti-seize to the thread and wind down the bottom pre-load ring until it contacts with the spring. Then, wind the spring and ring together until you have about 5mm of pre-load. If it’s a new spring or you want to set the sag – this is done with the bike back on its wheels – leave the top ring loose and the bottom ring there. If you pre-recorded your sag by measuring the pre-load on the spring before you started, you can use a pre-load ring spanner to tighten the ring until you reach the correct pre-load, then, tighten the top preload ring as a lock-nut to prevent the unit from turning.

10. REASSEMBLE YOUR BIKE

With the shock back together, you can reinstall it in your bike and reassemble the exhaust, airbox cover and seat. It may be helpful to have a mate jiggle the swingarm to help get the bottom shock bolt back into position. With the bike back together, set the sag by adjusting the pre-load. Finally, make sure the top pre-load ring is tight before going for your maiden ride on the new spring.

PRO TIPS WITH NICK DOLE

  • On KYB shocks the spring is a different diameter at each end. The small end should face up.
  • If you have already set the sag correctly, measure the length of the spring before undoing the rings to determine the pre-load. You can then reassemble without having to set the sag again.
  • Always use copper anti-seize on the shock threads to avoid binding.

 

Clutches

It takes a pounding from both the engine & the driveline, and no sympathy from riders either.

Click to download orginal article in Transmoto Magazine or scroll down to the bottom.
Courtesy of Transmoto Magazine.


MOTORBIKE CLUTCH DIAGNOSTICS

Understanding the critical connection between your engine and rear wheel.

The clutch is the poor tortured device that sits between your engine’s crankshaft and the back wheel, controlling the transmission of power. Some riders barely use it, while others use their clutch as a power modulater, brake, wheelie device, or gear-too-tall-and-don’t- want-to-shift device.

We typically don’t think about our clutch until it starts to slip or begins to feel jerky. Many riders reckon the friction (drive) plates are the only parts that wear, but all clutch components have a lifespan and will cause the deterioration of a clutch’s performance as they wear.

In simple terms, the clutch assembly is made up of a basket that is driven by the primary-drive gear off the crank, a hub that sits in the basket and locates both the clutch plates and splines onto the mainshaft, and a pressure plate that forces the clutch together to provide friction, and therefore drive. The drive plates and driven plates are commonly called friction plates and steel plates, respectively.

Drive plates are traditionally made from cork, but as this natural resource becomes more expensive, we are now seeing plates made from paper. The driven plates are commonly steel, although aluminum driven plates are often used in MX applications, as a heavy clutch assembly has a significant flywheel effect.

Four, five or six coil springs are used to compress the pack, with a throw-out bearing pushing against the spring tension to disengage the pack. The clutch springs are usually a coil, although diaphragm springs are commonplace on road clutches.

Over the next few pages, we’ll explain how these parts work, what goes wrong with them, how to diagnose problems and how to fix them.

DIRT BIKE CLUTCH ABUSE

To put a dirt bike’s clutch into perspective, when you drive down to the shops in the car, do you take a corner in fourth gear when you really should be in third, and just fan (slip) the clutch to break the back-end loose and get the engine up into the power? No. Do you hold the throttle flat and flick the clutch to change gears? No. In a recent Top Gear celebrity driving challenge, the clutch on their brand-new reasonably priced car lasted for only 26 miles of abuse … the sort of abuse that would be considered normal on a dirt bike!

Road bikes don’t suffer the same sort of clutch abuse, either, as they generally have more power and, as you’re always trying to be smooth, fanning is rare. Generally speaking, the larger the engine capacity, the less abuse the clutch will have to endure. For example, keeping a 125cc two-stroke in the meat of the power entails using a hell of a lot more clutch than a 530cc four-stroke. It’s also riderdependant. If you just hold the throttle open and modulate power delivery with the clutch – common among fast off-road riders – wear occurs fast.

Single vs Multi-Plate Clutches

On the face of it, single-plate clutches – found in cars, 4WDs and trucks – look a whole lot simpler than a dirt bike’s complex multi-plate clutch, but there’s good reason for it.

Multi-plate clutches are at the pointy end of the clutch world, being used on F1 and top fuel cars. Advantages include better feel from the larger surface area, a more controllable engagement point, more plates to share the wear, and oil to dissipate heat and contaminants.

We can often get away with only changing the drive plates in a motorcycle, but we are leaving ourselves open to problems if the other wearing parts – that are replaced in cars – are not inspected. For example, when you replace a car’s clutch disc, you also replace the pressure plate, spring(s) and throw-out bearing, and machine the drive hub.

The other important aspect of the multi-plate clutch is the overall pack thickness, and this is where you can come a bit unstuck using aftermarket plates. If you’re after replacement aftermarket wear plates, then it’s not only the physical dimensions that are critical – it’s also the thickness. If we have eight fibres at 3.0mm each and seven steels at 2.0mm, that’s a pack thickness of 38mm. By using aftermarket 2.8mm fibres, we have lost 1.6mm of thickness from the overall pack, significantly reducing the spring clamping load. It always pays to check the overall pack height, as we’ve even seen this problem happen with respected aftermarket suppliers.

The Throw-Out Bearing – opposes the clutch springs and opens the clutch pack up, so drive and driven plates can rotate independently. It can actuate on either the hub or pressure plate, but the result is the same. They almost never wear out unless starved of oil, or if mechanically damaged.

The Drive Plates – have little fingers on them, and are cork- or paper-lined. They start out at a specified thickness and wear over time. Be aware that if you have eight plates, 0.1mm of wear on each plate it might not seem like much, but that’s 0.8mm over the whole pack – enough to cause slippage when being worked hard.

The Drive Hub – sits in the bottom of the basket and is splined to both the driven plates and the gearbox mainshaft. It will wear on both the drive plate face and the driven face splines. The bosses that hold the clutch spring bolts are integral to the hub, so don’t go over-tightening them. If you snap one off, you’ll need to replace the hub.

The Basket – is where all the other clutch components are housed. The fingers of the basket are the second-fastest wearing item after the plates, as they transmit the engine’s torque from the primary drive to the plates. The basket also houses torsional vibration springs that dampen the engine’s pulses to protect the transmission.

The Clutch Springs – keep pressure on the clutch pack to produce friction. Coil springs lose free length over time, and should be checked on every clutch change. Any signs of blueing indicates high clutch temperatures. If there’s a problem it’s best to replace them, as they’re dirt cheap.

The Pressure Plate – is the first part you have in your hand when the clutch comes apart. It holds the pack together and has a bearing surface for the throw-out bearing. Pressure plates do wear, so inspect the drive surface. It should be smooth and not recessed.

Driven Plates – are either steel or alloy, and are splined to the drive hub to transmit the drive to the gearbox mainshaft. Alloy plates tend to wear quickly and contaminate the gear oil, but can be replaced with steel. Check them for warping and discolouration when changing a clutch.

The Judder Spring – isn’t found in all clutches; it’s more trailbike territory. If you have one, it sits at the bottom of the clutch pack on the hub, and offers an opposing spring force to the main springs. It makes the engagement pickup point softer and offers more feel to stop snatchiness off the line.

CLUTCH DISASSEMBLY

  1. Brake Calliper

Push down hard on the brake calliper to make the brake lever floppy. This gives you access to the clutch cover without removing the lever – easy.

  1. Remove Clutch Cover

Try not to tear the gasket when you unbolt the clutch cover, as it can be re-used. Then use the cover to house all the other parts you pull off the bike.

  1. Loosen/Remove Springs

As you remove the springs, note if they are directional. If so, there’ll be paint marks, or the springs will be progressive or beehive in design.

  1. Remove Clutch Pack

Remove the clutch plates as a stack. Hondas have a neat little holes for oversize fingers. Note down the pack order if the first and last plates differ from the rest of the pack.

  1. Remove Throw-Out Bearing

There is sometimes a ball bearing under the throwout bearing, so be careful as you remove it. Dropping it into the transmission is no fun. Fishing, anyone?

  1. Flatten Lock Washer

Use a sharp steel cold chisel to flatten the clutch hub nut lock washer. The wooden type can crack and splinter, contaminating your oil.

  1. Loosen Clutch Hub Nut

An air impact gun is the easiest way to loosen the clutch hub nut, but you can use a spanner by putting the bike in gear and holding the rear brake on.

  1. Remove Clutch Basket

With the nut removed, simply pull out the clutch basket. Keep an eye out for thrust washers and bearings that could fall into the transmission.

LEVERS

With enough leverage you can move the world, right? There are a few leverage points at work in both cable and hydraulic clutches, but the bottom line is that there is a trade-off between total lever movement and the effort to pull the lever in.

There used to be a trend towards shorty levers as they were more comfortable and crash-proof, but they make the clutch heavier to pull due to less leverage. The gumby-looking long levers give you greater mechanical advantage. There is also the option of moving the lever pivot point so it takes less effort to move the cable, but this comes at the cost of reduced cable travel. This is seldom a problem for race bikes, but can lead to clutch drag – and extreme heat – in trailbikes that sit for extended periods in first gear with the clutch in. You can also extend the actuating arm at the gearbox for the same effect.

CLUTCH CABLE

Why do we still use cables when hydraulic clutches have the benefits of being self-adjusting, not drying out, or getting full of dirt and giving you arm-pump in a nanosecond? There’s two reasons – cost and feel.

The cost benefit of cables isn’t just in the initial manufacturing, but also maintenance. Cables do wear out, but they are cheap to replace (unlike hydraulic clutches). Don’t bother trying to lube an old, dry, worn-out cable when $30-$50 will get your clutch feeling like new again.

In terms of feel, the pack only has to be separated by tenths of a millimetre to alter the amount of clutch plate slippage. A cable has none of the dampening effects found in a hydraulic clutch that result in a loss of feel, but you need to be pretty damn fussy (fast) to tell the difference.

Cable clutches can have a light pull with proper maintenance.

HYDRAULIC CLUTCH

Retro-fitted hydraulic clutch kits were popular in the late ’90s on Japanese bikes, but they were usually a poorly laid-out mess that was just waiting to fail. KTM changed our perception of how good a hydraulic clutch can be, but the downside used to be the frightening bill if you broke it. Now they’re not that expensive, with plenty of aftermarket parts available.

Fluid choice is always a cause for confusion. Magura recommends their own bio-hydraulic ‘blood’ oil, and Motorex makes a very good hydraulic clutch fluid. In a pinch, we’ve seen blokes use everything from 3wt fork oil to automatic transmission fluid. Brake fluid will work too, but isn’t good for the seals and lines.

A chain derailment can smash the slave cylinder, so a guard is well worth having.

CLUTCH CHECKS/DIAGNOSTICS

How do you know when your clutch is unhappy? There are a variety of symptoms, from a hard lever, dragging, slipping or a hard-to-find neutral, but most are easy and cheap to fix. Below is a list of the common symptoms, the associated problem, and what’s needed to fix it. These parts should all be checked when you have the sucker apart as a preventative measure, too.

Worn Drive Plates

Symptoms: The clutch slips under power; especially under hard acceleration in the mid-range.

Problem: The paper or cork is worn out or burnt, and can’t maintain friction against the driven plates.

Fix: Replace the lot.

Typical Cost: $65-$200, depending on the number of plates and whether you go OEM or aftermarket.

Warped Driven Plates

Symptoms: Hard to find neutral and a long engagement point. You’ve inspected the basket for notches, but it’s fine.

Problem: The driven plates are warped from heat. Put the plate on a piece of glass and try to slide a thin feeler guage under it.

Fix: Replace ‘em. Just the warped ones if you’re tight, but ideally all of them.

Typical Cost: $40-$120, depending on the number of plates.

Small Pack Height

Symptoms: You’ve replaced the drive plates and springs, but the clutch still slips.

Problem: You bought non-genuine plates so the overall pack height is thinner than stock. The spring preload is lowered.

Fix: Work out what the pack height should be, and use the bogus plates as ninja throwing-stars at the parts man.

Typical Cost: Bad mood, lost riding time, ridiculed by your mates.

Worn Springs

Symptoms: You have just thrown a set of fibre (drive) plates in to cure your slipping clutch, but the clutch slips again after a short while.

Problem: The clutch springs have lost their free length over time, and can no longer create the necessary pressure to create friction.

Fix: Replace ‘em. It’s quick, cheap and easy.

Typical Cost: $35-$50.

Worn Basket

Symptoms: Hard lever action with a new cable, bike jumps when you engage a gear, hard to find neutral, clutches don’t last.

Problem: The basket fingers have grooves in them.

Fix: File them out if you are stuck or tight, or buy a new one. A Hinson or Wiseco basket/hub/pressure plate combo is a good idea if you are a serial clutch abuser.

Typical Cost: 15 minutes with a file, or $250-$600 for a new basket.

Worn Damper Spring

Symptoms: Clutch rattles at idle, and is worse in neutral. There’s also backlash in the transmission.

Problem: The springs in the back of the basket have worn and need replacing.

Fix: If you’re lucky you’ll get away with new rubbers and springs, but you’ll usually need a new basket. Aftermarket baskets don’t include the drive gear, so you’ll need springs separately.

Typical Cost: $300-$500

Worn Throw-Out Bearing

Symptoms: A rattly noise when you pull the clutch in.

Problem: The throw-out bearing has had the sword. If it has overheated it will have a blue tinge. If there’s mechanical damage, munched steel should be a giveaway sign.

Fix: Newbie required.

Typical Cost: $10-50.

Flat Judder Spring

Symptoms: The clutch has lost its long, smooth engagement point, and is now either in or out.

Problem: The judder spring, usually a convex shape, has gone flat.

Fix: Get a new one, and use the flat item as a hamster hula-hoop.

Typical Cost: $25

AUTO CLUTCHES

There are a few auto clutches on the market, which all differ slightly. They are similar to a centrifugal clutch in that when the engine is idling, the clutch is disengaged. This disengagement point can be altered to a designated engine RPM, so engine braking is not lost on slow hill descents. The clutch lever will still operate as normal, with a lighter or heavier feel, depending on the product.

The main advantage is that you can’t stall the engine, so you spend less time fussing over the clutch at low speeds and in difficult sections like hills. It’s also harder to stall the engine with the rear brake, and poor clutch control is a thing of the past – just twist the throttle and go.

SLIPPER CLUTCHES

It’s possible to over-rev any engine mechanically. For example, if you come into a corner in fourth gear, bang it down two gears on the entry and let the clutch out, the rear wheel will spin the engine over faster than the rev limiter is set to. This is a common source of four-stroke engine failure, so a clutch that could slip on over-run was invented, also known as a back-torque limiter, or slipper clutch.

A slipper clutch can eliminate over-rev, and reduce the mechanical drag that compression braking brings. Another benefit is that, as the chain is not loaded up, the suspension works better, and the bike is more settled in corners.

Road racers have used slipper clutches since the ’80s, but owners of four-stroke motocrossers are starting to catch on to the benefits. They take a bit of setting up, as the point of slip/grip is dictated by the thickness of the whole pack, plus some optional cams and springs.

CLAKE LEVER

The Clake is a cool Aussie invention that looks like a hydraulic clutch, but with two master cylinders. One’s for the clutch, and the other the rear brake. As you pull the lever in, the clutch disengages first, and then the rear brake is actuated as you get closer to the bars. The engagement points are adjustable, so you can get more or less brake/ clutch. The rear brake pedal remains, and the clutch can still be feathered and fanned as normal.

Originally designed by a rider with a bad ankle, the advantages are numerous. You always have access to the rear brake, so right-hand turns and steep downhills become much easier. It also provides greater feel for the rear brake.

THE FUTURE

Constantly variable transmissions (CVT) have been used on scooters for decades. There has always been talk of them branching out of the scooter niche and into other motorcycles, but it has never happened. That’s because the drive belt is a weak link, and wouldn’t like the type abuse dirt bikes would throw at it. The need the keep the swingarm pivot and rear axle pivot the same length makes it interesting, too.

Honda invented an infinitely variable transmission that featured on the bike that won the All-Japan Motocross Championship in 1991, but all development on the technology seems to have gone quiet.

Husqvarna made three- and four-speed auto gearboxes in the ’80s, but they had a few reliability problems. When it was going it was great, with all the advantages of an auto clutch but no gear changes. But there was no engine braking whatsoever! Hopefully one day they will return.

There have been factory prototypes of electronically-controlled transmissions for many years, but none have made production. In a dirt bike, simple is usually best, as there are fewer parts to break.

WET VS DRY CLUTCHES

Dry clutches were last seen on dirt bikes in the late ’80s on factory bikes, but were lost when the AMA went to the production rule in 1986. Cagiva hung onto the dream for a few years in 125cc MX GP, but you won’t hear the distinct rattle at a motocross track today.

They have some advantages over a wet clutch, being fast and easy to service on the side of the track, with no oil loss. There’s also no engine oil contamination and cavitation, and the whole gearbox casting can be made much smaller. They are generally smaller for a given power output, too.

But there’re plenty of downsides, which is why all dirt bikes and most road bikes use wet clutches today. Dry clutches are loud and rattly, produce mountains of black dust, the baskets wear as fast as the drive plates, and they overheat in seconds when stationary and disengaged.

Today, you’ll only hear the rattle of a dry clutch as a Ducati rider fetches his café latte, drowning out the exhaust noise from his twin 54mm pipes.

OIL CHOICE FOR CLUTCHES

The oil that lubricates your clutch has to have some unusual properties. It needs to be capable of absorbing the shock loading of the transmission gears and lubricating the transmission bearings, but can’t do its job so well that the clutch isn’t capable of grabbing.

As the clutch relies on friction, the wrong oil can cause headaches. Some automotive engine oils contain additives such as friction modifiers, but the additives will permiate the clutch plates and give you a slipping clutch. The best oil for a clutch is an automatic transmission fluid, as it’s designed for wet cork clutches and the planetry gears found in automatic car transmissions. Unfortunately it’s not designed to handle shock loading, which is very common in a dirt bike as it gains and breaks traction. ATF fluid can be used in a pinch in two-strokes, but it’s better to use specialist gearbox oils for wet clutch motorcycles.

Four-strokes that share the engine and transmission oil make for a bigger dilemma, as the oil has to cope with an internal combustion engine as well. Clutch slipping and drag issues can still occur with some big-name specialist motorcycle oils, so if you feel your clutch is not working as well as it once was and you have changed oil brands recently, try another brand.

 

Changing an Engine Timing Chain

Timing is everything. Especially when it's measured in milliseconds.

Click to download original article in Transmoto Magazine or scroll down to the bottom.
Courtesy of Transmoto Magazine.


HOW TO REPLACE A FOUR-STROKE’S TIMING CHAIN THE RIGHT WAY

Replacing a timing chain isn’t a sexy job. It doesn’t offer you any extra power to thank you for your efforts, and it’s not like fitting a shiny alloy part where everyone in the pit paddock can admire your bling handiwork. However, the job is absolutely critical, as a broken or loose chain that causes your camshafts to skip a tooth could see the likes of the Chernobyl disaster replicated between your legs – costing upwards of $2500 to fix. Basically, it’s mechanical insurance.

A timing chain (naturally only found on a four-stroke) has the important job of keeping the camshaft – and therefore the opening and closing of the inlet and exhaust valves – turning in exact unison with the crankshaft. Old-school donks had foolproof gears turning the camshaft with pushrods transferring the force to the valves, however the lighter and more powerful overhead cam technology has seen those gears replaced with a chain.

Timing chains are pretty hardy these days and rarely need replacement, but it’s better to be safe than sorry. It’s a good idea to stick to your manufacturer’s replacement recommendations. Also, check the slack in the chain whenever you check your valve clearances by pulling the chain at the top of the camshaft sprocket and seeing how much play there is – any more than half-a-tooth of slop and it’s time to replace her.

Over the next three pages, Teknik’s Nick Dole explains how it’s done right.

 

DIY WORKSHOP

In this final part of Transmoto’s four-stroke top-end rebuild series, we explain exactly what is involved in replacing a timing chain. Last month, we looked at how to replace and inspect your bike’s piston and rings, and the month before, we looked at how to check and adjust the valve clearances. This issue builds on what’s covered in those features, so if you missed either, go to www.transmoto.com.au and you’ll find the first two features in their entirety.

 

TOOLS YOU’LL NEED

  • Spanners, T-bars and Socket Set
  • Allen keys
  • Tie wire
  • Pliers
  • Magnet
  • Vernier calipers
  • Circlip pliers
  • Impact gun
  • Torque wrench
  • Flywheel puller

 

WHAT IT’LL COST YA

  • Labour: 1.5 hours
  • Timing chain: $60

 

1. STRIP & REMOVE THE CAMS

Before you begin, give your bike a thorough wash to avoid getting grit and sand into your engine. Remove the seat and tank, and then follow the steps in the valve clearance adjustment story from two months ago (and online) to pull off the camshafts. There’s no need to remove the buckets and shims if the valves have already been adjusted.

2. REMOVE STARTER MOTOR THROW-OUT GEAR

Most timing chains are a single loop, and are never broken or joined. Instead, they’re replaced as a whole unit from around the crank sprocket (behind the flywheel). To gain access, bikes with starter motors will need the throw-out gear removed, and possibly even the starter motor itself – if the seal with the flywheel cover is stiff.

3. PULL OFF THE FLYWHEEL COVER

With the starter motor and throw-out gear removed, gently pull off the flywheel cover, stator and gasket. Keep track of where the bolts belong as they’re often different lengths around the cover. Don’t lever the cover off from just one point as it may crack. Instead, carefully work your way around with a small screwdriver.

4. CLEAN THE FLYWHEEL & MOVING PARTS

With clear access to the left side of the engine, now’s a great time to give the accessible parts a thorough clean. Even though different oils have better detergent qualities than others, even the best quality oils will see some soot and grime build-up over time and use. Hit what you can with a degreaser spray and a brush if necessary.

5. REMOVE THE FLYWHEEL NUT

The flywheel nut is one of the tightest fasteners on your bike. While it is possible to lock the engine up to prevent the flywheel from turning and then undo the nut with a spanner, the stress on the engine and the chance of bending something, means this isn’t the ideal method. Instead, a pneumatic or electric rattle gun is definitely the way to go here.

6. PULL OFF THE FLYWHEEL

The only special tool required for this job is a flywheel puller, designed to remove the flywheel from the tapered end of the crankshaft. Simply screw the nut attachment onto the end of the flywheel, then the main puller body onto the flywheel itself. As you tighten the bolt on the puller, the flywheel will be pulled off the end of the crankshaft.

7. REMOVE STARTER MOTOR GEAR

As you pull the flywheel off, be sure to grab the woodruff key (a semi-circular metal disc that locks the two components together) from the groove on the crankshaft. Then, remove the large starter motor gear on the crankshaft to reveal the timing chain.

8. REMOVE THE TIMING CHAIN GUIDE

The final step before removing the chain is to pull off the timing chain guide. This is where the bottom end of the rear-side timing chain slider mounts, and is designed to hold the chain onto the correct tooth on the crank gear so you don’t risk skipping a tooth as you adjust the valve clearances. Simply remove the two bolts holding it in place.

TIMING CHAIN TENSIONER

As the name suggests, an automatic timing chain tensioner automatically applies the correct tension on a timing chain by pushing on the rear timing chain slider. That in turn takes up any slack as the chain naturally stretches and loosens. To take the tension off the chain, simply remove the cover bolt on the back of the tensioner, then unscrew the bolt until you feel a click, whereby the tensioner will automatically loosen off. When retensioning the chain, wind the bolt in until you feel a similar click, and the tensioner will automatically adjust to the correct tension.

9. REPLACE THE CHAIN

With everything removed, simply let the chain drop and pull it out as a single loop from around the crankshaft. To put the new chain on, tie a piece of tie wire around the chain and poke it up through the cases, allowing you to pull the chain up from the top. This photo shows the new chain before it gets fed into the engine’s cases.

10. REASSEMBLE THE ENGINE

With the new chain in place, reassembly is in the reverse order, including the steps from the previous valve adjustment story. The critical aspect of the reassembly is getting the correct torque on the flywheel nut. If you’re using a rattle gun and are not confident, ask a mechanic or a mate who knows what they’re doing to help.

TIMING CHAIN SLIDER

While there’s no need to remove the front slider when replacing the timing chain, you do when you pull the head off to replace a piston. The trick then becomes getting the slider to seat correctly when reinstalling it. This photo shows the bucket seat that the lower end of the front slider sits in, as well as the counter-balancer (semi-circular device) used on most modern thumpers to reduce vibration from the engine.

 

Changing A 4 Stroke Piston

How well do you know your engine? If you're a beginner, here's your chance to learn, and if you're experienced, here are some great tips.

Click to download orginal article in Transmoto Magazine or scroll down to the bottom.
Courtesy of Transmoto Magazine.


4 Stroke Engine Piston Rebuild

How to measure and inspect your four-stroke’s piston, rings and bore

The most internal part of any 4 stroke internal combustion engine is the piston. In this article our resident motorbike guru Nick takes you through the step by step of removing, cleaning, diagnosing and rebuilding the very core of your engine.

Pistons, rings and barrels are consumable parts in high-tech four-strokes – no matter how well you treat them, they’ll wear out. Manufacturers generally recommend that you change your bike’s piston every 40 to 80 hours. However, plenty of owners get away with over 150 hours without a rebuild on a 450cc. on the other hand, a fist-full of sand or a stray piece of metal can leave the inside of your engine looking like a priceless Picasso artwork that’s been attacked with 40-grit sandpaper. And a knife! So, if you’re an average rider, it’s a good idea to pull the head and barrel off your bike once every couple of years and inspect the condition of the piston and bore. At the very least, throwing in a new set of rings and inspecting the condition of the wearing parts is cheap insurance against a seizure or a thrown bearing.

Given the complexity of a modern four-stroke, there are plenty of owners who couldn’t describe what the inside of their engine looks like – let alone how to rebuild it. Replacing a piston shouldn’t be undertaken by someone with limited mechanical experience, but it isn’t the hardest job, either. The purpose of this story is two-fold: to give those who send their bike to a mechanic an idea of what’s involved in the process, and to arm those competent home mechanics with the skills and tips needed to get the job done properly. Nick Dole explains how it’s done.

TOOLS YOU’LL NEED

  • Spanners, T-bars and Socket Set
  • Allen keys
  • Tie wire
  • Pliers
  • Magnet
  • Vernier calipers
  • Circlip pliers
  • Impact gun
  • Stanley knife
  • Torque wrench

WHAT IT’LL COST YA

  • Labour: 2 to 4 hours
  • Piston & Rings: $120 to $250
  • Gasket Kit: $100

1. REMOVE THE VALVE TRAIN

This story kicks off with the valve train, buckets and shims removed. This was covered in last month’s feature, and if you missed it, head to www.transmoto.com.au and follow the steps through to that point. Make sure that your bike is clean and that you’ve measured and taken notes of all the buckets and shims you’ve removed. Without notes, you won’t know which shims and buckets belong to what valve when putting it all back together.

2. DRAIN THE COOLANT

Taking the barrel off requires a radiator hose to be removed, so you’ll need to drain the coolant from your bike. This can provide a convenient time to do a cooling system flush while you’re at it. To remove the coolant, remove the radiator cap, then take out the drain bolt on the water-pump cover – it’s the one with a – copper washer. With the coolant drained fully, take off the top radiator hose.

3. REMOVE THE EXHAUST

Accessing the head and barrel requires the exhaust to come off, too. Before you even start to unbolt anything, give all the bolts a thorough spray with penetrating oil and leave it for ten minutes, as the engine’s heat is almost guaranteed to have stiffened the bolts up. Then unbolt the muffler and header pipe.

4. REMOVE THE CARBURETOR OR THROTTLE BODY

As well as the exhaust and top radiator hose, you will also need to remove the carby, or throttle body (if your bike is fuel-injected). This means removing the throttle cable(s) from the throttle cam, then pushing the carby or throttle body away from the inlet rubber on the head. It’s often easiest to pull the subframe off, giving you room to move when taking the head and barrel out later.

5. LOOSEN THE HEAD BOLTS

With the valve train removed and the timing chain secured up to the frame with a piece of tie-wire, loosen then remove the head bolts. There are typically four bolts that sit under the valve train. On some bikes, those clever engineers spectacularly fail to think about whether the bolts can be removed from the engine when it’s still in the frame, so you may need to loosen the engine mounts on your bike to allow enough movement get the bolts out.

6. LEVER THE HEAD LOOSE

If the head gasket has done its job properly, the sealant that is preimpregnated into the gasket will have stuck the barrel and the head together. To lift the head off you’ll need to pry the head up at different points to lift it up from the dowel pins holding it in place. There are usually two prying points on either side of the head to work off. Don’t try and jam a flat-blade screw driver down the gap as you’re sure to damage the mating surfaces.

7. REMOVE DOWEL PINS

Holding the head in alignment to the barrel are four dowel pins. In order to clean the gasket surface, you’ll need to remove these dowels from the head and bore. The best way to do this is using a pair of side-cutter pliers. This will only leave a tiny score on the surface of the dowels and will prevent you from squashing or deforming them, rendering them unusable. Also, it’s worth noting what you see on the head. You can tell from the soot covering the head and valves that the bike has been running too rich.

8. CLEANING THE HEAD

With the head off the bike, now is the perfect time to clean away any built-up grime, soot and gasket remains. Simply cover the head in degreaser, then use a Scotch-brite pad (we buy it in 20m rolls from a panel beater supply shop) to clean the surface of the head. There’s no need to go to wild here as you don’t want to scratch the head or gasket surface, but make sure all the old gasket glue is completely removed.

9. REMOVE THE TIMING CHAIN SLIDER

Before removing the barrel, you’ll need to pull out the plastic timing chain slider. This almost always sits at the front of the engine, and can simply be pulled out. The slider has two lugs formed into the plastic that nestle into a groove on the top of the barrel, thus ensuring the slider stays put. When re-installing the slider later, make sure that the tip of the slider and the lugs are properly aligned. in the timing chain replacement story next month, you’ll see where the base of the slider sits in the cases.

INSPECTING THE BORE

Most modern four-stroke barrels are made of aluminium with a Nikasil plating on the bore. Although the Nikasil coating is tough enough to withstand a beating from the piston rings, it is also relatively thin, and will wear down over time. If you have a cylinder bore gauge micrometer, measure the diameter of the bore up and down the length of the stroke and at several points around the circle of the cylinder, and compare the measurements with the manufacturer’s specifications. If not, you can get a good idea of the wear on the bore through a close visual inspection. Look for any deep scours in the bore and run your finger lightly around the cylinder to feel for any inconsistencies or scratches. This bore has about 150 hours on it and doesn’t have any major markings, however the bore was getting close the wearing through the Nikasil to the aluminium in some points. We decided to re-use the barrel to get another 50 hours from it, however a safer bet would be to replace the barrel or get it re-plated. If you re-use the barrel, either give it a quick hone using a honing tool or a very light rub with a Scotch-Brite pad to remove any glazing on the cylinder.

10. REMOVE THE BARREL

With the timing chain slider removed, the only thing getting in the way of the barrel’s removal is the timing chain. A long piece of tie wire twisted around the timing chain allows you to simply let the chain drop down into the engine cases and be easily retrieved later. Then pry the barrel from the cases and pull the barrel over the piston. You may need to rotate the engine (via the crank nut) to get the piston lower in its stroke if you have limited removal room in the frame. Clean the gasket surface in the same way that you did with the head.

11. REMOVING THE PISTON

The final step in the disassembly process is removing the piston. This is an easy step, but can lead to a world of pain if you lose a circlip down into the engine cases. To avoid this, grab a clean rag and wrap it tightly around the conrod then fanning out over the gasket surfaces, so that anything dropped will land on the rag. Use a pair of circlip pliers to remove the circlip out from one side of the piston and the end of the gudgeon pin. Then push the gudgeon pin out to remove the piston from the conrod.

12. OIL UP THE NEW RINGS

After you’ve inspected the piston, rings and bore and set up the new rings on the piston you’re going to use (see the sidebars on those steps), pour some heavy oil on the rings and distribute it around the piston. This provides some lubrication for when you first start up the bike after the rebuild and prevents any initial scouring.

13. INSTALL THE PISTON INTO THE BARREL

When reinstalling the piston and barrel on the bike, it is possible to install the piston first then place the barrel over the top, however this can be a fiddly process. The best method is to partly install the piston into the barrel on the workbench, where you can easily pinch the rings together and ensure they’re lined up correctly. While you’re there, install a circlip on one side of the piston to make life easier when you’re putting the gudgeon pin through the conrod in the next step.

INSPECTING THE PISTON & RINGS

Aside from checking for obvious wear, scrapes or gouges on the piston, the most important inspection is to check the wear on the rings and piston’s grooves. To do this, take the rings off the piston. Then check each ring in turn to see how far the ring can turn in the groove when held in the same way as the above photo. If it can move back and forth more than about 10 degrees, it’s a fair bet that the rings and grooves are worn out, and that a new piston and rings are called for. Also, pay close attention for any signs of wear on the gudgeon pin, which could become exacerbated with use. There are plenty of aftermarket options for pistons and rings, but the genuine Yamaha items we used are of the highest quality and aren’t too expensive – the piston, gudgeon pin and rings cost around $250 all up.

14. REINSTALL THE NEW PISTON & BARREL

Before you go putting the piston on, make sure the gasket surface on the cases is clean and that you’ve laid a base gasket out on the surface and over the conrod. Always use a new top-end gasket kit – the genuine Yamaha kit we used costs $100. Then grab the barrel with the piston already in place. Slip the gudgeon pin through the piston and conrod, then insert the second circlip, making sure it’s firmly in its slot. An important trick here is to ensure that the eyes of the circlip are facing either directly up or down in the slot, in line with the direction of travel of the piston. if the circlip gap is placed at three or nine o’clock (when viewed from the side), the G-force the circlip is subject to when the piston changes direction at the end of the stroke could cause the weight of the circlip to push against its own spring tension and come out of place.

15. REINSTALL THE HEAD

With the barrel secured and the timing chain slider reinstalled, place the dowels into the top of the barrel to align the head. With the gasket surface clean, seat the new gasket into position, then place the head onto the cylinder. Using the wire connected to the timing chain, pull the chain up through the head and tie it up to the frame of the bike. Push the head down onto the dowels and ensure the gasket is seated well, then check that the timing chain slider remains seated.

16. ADJUST THE HEAD TENSION

With the head in place, bolt the head and barrel to the cases. Of all the bolts on your bike where it is important to get the correct tension, the head bolts are probably the most crucial, so use a torque wrench. If you’re re-using the head bolts, they have already been stretched once, so use plenty of caution and try to ‘feel’ the bolt stretch. To remove any unwanted friction, use a dab of copper anti-seize grease on the thread and under the bolt head.

17. REINSTALL

With the head and barrel back in place and correctly torqued, reinstall the exhaust, carby or throttle body, and radiator hoses. Then follow the steps in the valve adjustment story to put the valve train back together and reinstall the timing chain, and then fill the cooling system with fluid. Put the top engine mounts back on, reinstall the throttle cables and put the tank and plastics back together, and you should be good to go.

SETTING THE PISTON’S RINGS

When putting the rings on the piston, it’s important to place the ring gaps at certain intervals around the bore to ensure you get as much compression as possible. Sure, they might rotate a little over time, but you should get the intervals between each ring right in relation to the others to reduce the chance of all the gaps lining up and you losing serious compression. Most manufacturers recommend to place all ring gaps 120 degrees away from each other. That is fine, however a lot of engine builders use a different approach. Imagine that the front of the piston is 12 o’clock. They place the top compression ring gap at 3 o’clock, the second compression ring gap at 9, the top oil ring gap at 3, the oil scraper gap at 12, and the bottom oil ring gap at 9 o’clock.

 

Loud Bikes & Locked Gates

Aftermarket Mufflers are really popular, and make more power with less weight. Or do they?

Click to download orginal article in Transmoto Magazine or scroll down to the bottom.
Courtesy of Adventure Rider Magazine.


Thoughts on aftermarket mufflers and adventure bike riding

What aftermarket mufflers definitely do is make more noise. And constant noise pollution can make enemies of friends pretty quick. We go through the basics of muffler design and construction and explain the pros and cons of each.

Aftermarket pipes are a favourite of nearly all bike owners. But are they a must-have or a marketing concept? Nick Dole, owner of Teknik Motorsport, is all about performance. Glossy photos, big-budget marketing campaigns and loud opinions on internet forums cut no ice at Teknik. Nick’s pay cheques are written on chequered flags and dyno charts. He shared a few thoughts on after-market pipes and adventure riding.

[Main image: Those running loud pipes are costing all the sensible riders access to riding areas. Stock pipes are not only usually quieter than aftermarket pipes, they often work better in an adventure application.]

Adventure riding means different things to different people. For many, it’s an opportunity to get away from the routine of daily life, see new places, forge new friendships and explore. While we do all this, we leave a footprint on the places we ride. Not just tyres and the odd ploughing from a DR650 bashplate, but loud, echoing noise.

The noisy-bike debate

Like it or not, most adventure bikes get into some sensitive areas, and the pulses from a single-cylinder bike do travel in gullies and bounce off valley walls. Sometimes they’ll echo on for kilometres. We then have a question: do we care if the local inhabitants hear us riding in their little piece of Utopia?

While local residents don’t have the final say on what forest trails are left open, there’s been heavy petitioning at times to keep bikes (and 4WDs) out of certain areas.

One of the first items on peoples’ shopping list with a new bike is a pipe. Why? General perception is that stock units are heavy, ugly and cost power. Is that true or false?

The noisy-bike debate: Performance gains and losses

The noisy-bike debate has been going on for as long as I can remember. It’s not just the risk of pissing off locals, but have you ever followed a bike with a noisy pipe for a few hours? It’s enough to make you want to pass them or drop back.

A few decades ago, when the two-stroke was king, Italian plastics giant Acerbis made a plastic muffler. I had one on my Six Day KTM 250. Coupled with the factory Slechin double-wall pipe it made great power and was very quiet. All the KTM Six Day bikes had that exhaust combo for the event. It was so quiet you often had to shout at people on single trail to get them to move over. Acerbis only made the mufflers for a few years. They weren’t the biggest sellers, and the public preferred noisy mufflers like the FMF and Pro Circuit shorties.

Shaun Reed showed us all how much we were kidding ourselves at the 1994 A4DE. He dominated the entire event on a TTR250 with a stock muffler. From memory they were calling him “the whispering killer” or something like that.

So, what does an aftermarket pipe add in the horsepower department?

It depends entirely on the bike. Taking the DR650 as an example, about five horsepower is the gain. The bike isn’t overly powerful to start with, so you really feel the difference. A WR450F is a different story. The stock muffler is actually very good, especially with the GYTR insert. Can you really ride a 450 to the point where you need more power? Most top enduro guys are looking for ways to tame a 450 down. The aftermarket pipes for fourstrokes are performance orientated, and the power is made mostly higher up in the RPM range. That’s not great for long-distance work.

What about the weight, then?

True, some stock, steel mufflers are pretty heavy and there’s often a few kilograms to be lost. I’m not sure of the relevance to this on an adventure bike where we tend to load them up with between 10kg and 30kg of gear, but everyone considers this another justification.

I will say this about heavy, ugly stock pipes: they are durable! I’ve seen and welded up a lot of aftermarket pipes that have cracked, fallen apart and generally self-destructed. When was the last time you saw a stock pipe crack and fail?

Muffler types

Seeing as exhaust swaps seem unavoidable we can break them down into three main types to help you work out what noisemaker you should be more inclined to spend your hard-earned on.

The first is the mechanical baffle type.

Most stock pipes are mechanically baffled. The exhaust has to find its way through a labyrinth of plates, tubes and holes. While there may be some sound-absorbing material, it’s not replaceable and lasts forever anyway. From all these tubes and plates comes weight, and there’s usually a double-skin too, which keeps the outside of the muffler cooler and is a consideration for soft bags that push sidecovers on to the exhaust. The manufacturers do a lot of durability testing, so while it’s heavy, powersapping and ugly, at least it won’t fall apart. This is something you should consider if you plan on being away from home for a few weeks or months.

Next up is the perforated-core style that needs packing.

A perforated (‘perf’) core is a steel tube with lots of holes in it surrounded by sound-absorbing material – usually fibreglass packing. All performance motocross bikes are perforated-core only. There’s some mechanical baffling used at times, but it’s fairly minimal. Most aftermarket pipes are perforated- core only, and that’s why they’re so damn loud. There are exceptions – like the FMF Q Core – that are a mix of mechanical and perforated.

While these pipes are loud stock, the real issue is when the packing, usually glass fibre, gets loose and starts blowing out the end. You can watch it happen. Rev a bike with a motocross-type muffler and watch the little shards of glass packing flying out. Once the packing gets loose things go downhill very quickly. Not only does it lose power, it also makes more noise and the core is unsupported, leading to cracking. If you have a typical FMF/Yoshi/Pro Circuit muffler on a single you’ll need to repack as soon as the bike shows any increase in volume at all. All manufacturers sell repack kits, and you can also purchase quiet end caps for most of these pipes. So you can have the lightweight look and power without annoying the guy riding behind you and buzzing koalas out of their trees.

[Left image: A well-used Barrett muffler. It’s several years old but still in great condition. They’re very durable, and that’s a big consideration if you’re planning to cover big distances.]

Perforated core with lifetime packing

There are not a lot of pipes in this next category. Staintune and Barrett are the two most prominent. They don’t use a glass-fibre packing, they use stainless steel packing and it seems to last forever. Both have quiet inserts supplied with the pipes (not as optional extras). The Staintune gets the nod for durability too, with many units in service at well over 100,000km.

You can borrow a bit of technology to transfer into your glass-packed muffler by wrapping the perforated core in stainless-steel wool for a layer or two. This will protect the glass material from being blown out. Any industrial-supply company will be able to order the stainlesssteel wool in for you. The longstrand fibreglass packing is available free from yours truly. I hate unpacked mufflers so much I give the packing away free in some vain hope it’s helping the collective masses.

[Right image: Free muffler packing! Nick is so keen to keep bike noise levels acceptable that he makes quality packing available free to those smart enough to use it.]

Baffled

It should be noted multicylinder bikes don’t have as many problems with packing blowing out of mufflers as singles. The pressure-wave pulsing of a single seems to dislodge the packing pretty quickly.

If you just cannot have a stock muffler, my suggestion is to get one that either needs no repacking (Barrett and Staintune for instance, and run the ‘quiet’ inserts), or run cans with plenty of surface area to absorb noise, like the twin mufflers on the Ténéré 660s. They do a good job even in perforated, glass-pack form.

Buying a motocross-inspired muffler for an adventure bike is just asking for the world to hate you and, in turn, the rest of us.

Is your bike too noisy?

Do you need to wear earplugs? Do your mates hate following you? Do you get a headache from your own noise? Do people give you a dirty look when you ride past? If that’s you, do something about it before we alienate the general public even more.

If you just love the sound of a noisy motorcycle, go drag racing and stay the hell away from the rest of us.

 

Teknik Tapered Wire PDS Springs

WP's PDS (no-linkage) rear suspension is simple, light & low maintenance. But not smooth or progressive.

Click to download orginal article in Transmoto Magazine or scroll down to the bottom.
Courtesy of Australasian Dirt Bike Magazine.


TEKNIK'S TAPERED WIRE PROGRESSIVE SHOCK SPRINGS HELP MAKE THE PDS AS SMOOTH AS A LINKAGE SYSTEM

Could Teknik’s tapered-wire springs deliver the predictable progression that’s eluded WP’s PDS for 10 years?

WP’s PDS shock absorber first appeared on KTMs and Husabergs a decade ago. The no-linkage system is great for its simplicity, low maintenance and low weight, but not everyone likes the way it rides. Each year, KTM has introduced significant changes to springs, valving and other internal components to improve the shock’s performance. And in 2007, the Austrian factory made the biggest change when they laid the shock further down in the bike. But despite all this effort, there remains very little consensus about how to best set up a KTM’s rear-end; or even whether a straight-rate (linear) or progressive-rate spring is preferable. And with all the spring options now available, the market seems genuinely confused.

A couple of years ago, Sydney-based suspension tuner Nick Dole, from Teknik Motorsport, added another option to the mix – a revolutionary new shock spring with progression created by the tapered wire in the spring itself, rather than by the way the coils are wound. Despite struggling to market the concept, Teknik has notched up some success with its tapered-wire springs, so we figured it was time to have a closer look at this Australian innovation.

RACE VS T-SERIES

SPRING PROGRESSION

Teknik offers two tapered-wire spring options. On both springs, the inside diameter of the coil remains the same, while the outside diamter tapers slightly due to the tapered wire. Unlike more conventional progressive-rate springs, the pitch remains the same for the entire spring (so the coils remain equal distance apart), and the taper of the wire itself – something Dole claims can be manufactured to very fine tolerances – delivers the progression. Interestingly, both spring options are priced below KTM’s $280-$300 OEM WP progressive springs.

The RACE spring:

  • The initial portion of the coil is made from a constant-diameter wire (from 11 to 14mm, depending on rider weight). It then has a tapered mid-section, and reverts to a straight section (approx 8mm diameter) for the final few coils.
  • Fitting this spring must be accompanied by a re-valve.
  • It is available in nine rates (coded A through to I) to cover all riders from 45 to 110kg.
  • Set up to run a conventional 38-42mm of static sag, and 113-118mm of race sag. The Race spring will require a lot more preload (8-10mm, compared with 6mm on the T-Series) to create these same sag settings.

COST: $240 (spring), plus $219 (re-valved to suit), marketed primarily to racers.

The T-SERIES spring:

  • The lower portion of the coil is made from a constant-diameter wire (from 11 to 14mm, depending on rider weight). It then tapers gradually all the way to the spring tail at the top.
  • It is not as progressive as a Race spring, as the wire’s taper is not as pronounced and its initial rate is firmer than a Race spring’s.
  • It is available in five rates (T-3 to T-7), covering riders from 65 to 120kg.
  • It’s set up to run a conventional 38-42mm of static sag, and 113-118mm of race sag.

COST: $240 (spring), and marketed to trail and enduro riders.

BIRTH OF THE TAPERED SPRING

“Ken Wheeler from Team Motorex KTM had been grinding a few mils of end condition into the shock springs he was using on Tye Simmonds’ bikes and getting some good results,” says Teknik’s Nick Dole. “It was creating a more compliant ride in the first part of the stroke without compromising bottoming resistance as you moved further into the stroke. So Ken then asked me for springs with softer starting rates.

“At the same time, I’d started working with an Australian spring manufacturer, after a rally car suspension guy called Jamie Drummond told me they had the capability of manufacturing tapered-wire springs.

“We sent the manufacturer some shock springs from Factory Connection, Eibach, Race Tech and Langston Racing, who all make progressive-rate springs using a constant-diameter bar. In other words, all those springs were creating rate-progression conventionally – by altering the pitch of the coil, or the coil spacing. And, as Ken and I found, manufacturing tolerance issues were restricting the performance of those springs.

“Springs that were supposed to be the same rate, clearly weren’t. It turned out that pitches on pretty much all the major brands’ springs weren’t very consistent. Making a progressive spring by altering pitch opens up a can of worms in the quality control department.

“It dawned on me that these tapered-wire springs could help overcome the long-standing problems with the PDS shock; that they could more consistently and reliably produce exactly the spring rate ranges required because it’s easier to control the wire diameter than it is the coil’s pitch. This is exactly what our manufacturer had already discovered with car springs, and why they’d invested millions in equipment that could machine a taper into the wire.

The graph compares the resistance offered by a number of progressive-rate shock springs (WPs plus aftermarket options), all of which are marketed to suit a 70-75kg rider. The tester measures spring force only (does not take valving into account) over the 110mm of travel in each of these springs, which translates into more than 300mm of rear-wheel travel.

What’s interesting is how initially both WP-5 and WP-6 options are relatively firm and how they don’t offer much progression as the shock moves into its stroke. Each of the aftermarket shock springs have a softer initial rate and all end up firmer than the WP shock springs late in the stroke, but their progression ramps up very quickly in the mid-stroke. They are therefore likely to rely more heavily on valving to create a predictable rate of progression.

Teknik’s Race spring has the softest rate initially and matches the firmest springs’ resistance at full travel, but it makes the transition over a much smother arc. The idea is to therefore create a compliant ride in the first part of the stroke and still offer plenty of bottoming resistance. In principle, the Race spring’s smoother progression should be a whole lot easier for suspension tuners to match with the valving set-up. Teknik offers dealers two setting cards to make valving easy and/ or an optional shim kit.

“Manufacturing tolerance issues were restricting the performance of the conventional progressive-rate springs.” Nick Dole

THE PDS HISTORY

Over the past decade, WP’s PDS shock absorbers have retained their original 18mm shock shaft, 50mm-bore reservoir and twin-piston set-up. But they have also seen lots of changes – both from the factory and aftermarket suspension tuners – to help get them working better. Straight-rate (linear) aftermarket springs were available in the early days (2000-2001) before the factory embraced them in 2004.

There have been significantly revised valving specs, new pistons, new needles, telescopic needles, different progressive spring designs and bladder kits. Some tuners have even removed the secondary piston completely!

In broad terms, all these measures have been aimed at making the KTM’s rear-end plusher and more compliant on small bumps – without compromising bottoming resistance – and more stable through braking bumps. It’d be fair to say the mods have produced pretty mixed results on the whole. And certainly, no one has got it good enough for a top AMA rider to want to race a full season on it.

The most significant change to the PDS system came in 2007, when the shock was laid further down in KTM’s SX models, with the EXCs getting the upgrade the following year. This allowed the use of lighter springs and made the progressive-rate springs easier to get working more effectively. It also prompted Teknik to invest in the development of the all new tapered-wire shock springs.

MOTORCYCLE SPRING FACTS

  • All motorcycle shock springs have, until now, used a straight bar. That is, the wire remains at a constant diameter for the length of the spring.
  • With all other things being equal, the closer the coils are on a shock spring, the softer the spring rate. The further apart the coils, the firmer the spring.
  • Progressive-rate springs incorporate both tight-wound and spaced-out coils to deliver a progressive rate of resistance to compression. To achieve this, the pitch of the coils must change (that is, the angle from horizontal becomes more or less steep).
  • Virtually all late-model Japanese bikes with linkages use straight-rate springs, whereas KTM has used both progressive and linear.
  • One of the hallmarks of a well-made spring is that its tail will touch the first coil as soon as it has any pre-load on it. When the tail doesn’t touch the coil (whether by design or a gap being created with a grinder), this is called “end condition”. It creates a softer initial spring rate until the tail comes into contact with the coil, from which point it becomes progressively firmer.
  • A spring’s resistance is position-sensitive. Valving is velocity-sensitive.
  • KTM’s WP springs are Dutch-made. Europe winds its springs to the left, while springs made in America and Australia generally wind to the right.

“That was at the beginning of ’08, and after a lot of trial-and-error we got to the point where we offered eight different spring rates, and valving specs to match. They’re available for the ’07 SXs and ’08 EXCs onwards – that is, the models with the shock laid down further in the bike. It physically wouldn’t have been possible to do what we have with the tapered springs on the earlier KTMs with a more upright shock, as their springs were just too stiff and not conducive to the progressive effect the tapered-wire springs can deliver.

“I only wish we’d started developing this in 2002 as it appears that KTM may be returning to a rising-rate linkage set-up for the SX models in 2011 onwards.”

THE THEORY BEHIND TAPERED WIRE PDS SPRINGS

The basic idea behind the tapered-wire progressive spring is not new. It aims to create a more compliant ride in the initial part of the stroke, and a more linear progression in spring rate as the shock travels into its stroke. The Teknik guys claim the tapered-wire progressive springs can more accurately and predictably recreate the sort of mechanical progression offered by a rising-rate linkage. This means better traction out of corners and more stability through braking bumps.

TAPERED WIRE PDS SPRINGS IN PRACTICE

So has the tapered idea met with success? “The reality is, despite the results we’ve had with the likes of Tye Simmonds and Ben Grabham, it’s been a very hard sell to dealers,” concedes Dole, “mainly because you must re-valve the shock when you fit our tapered-wire Race spring. “Since the Race spring has a lot more spring-force in the bottom part of the stroke, the rebound damping in particular will try to catapult you over the bars if you run the standard valving. This is why we were sort of forced to introduce the T-Series tapered spring. In some respects, the T-Series is a compromise, but it means you can still achieve performance gains over the conventional progressive-rate springs, simply by replacing the spring. It’s as progressive and predictable as we could get it, without causing havoc with standard valving.”

Accordingly, Teknik has ended up marketing the Race springs to serious racers, and the more cost-effective T-Series springs to the trail and enduro guys. Dole believes the choice is largely application dependant.

“Trailriders and enduro guys tend to prefer a spring that is less progressive – one that will absorb big hits with a lot of shock movement, while keeping the heavier motorcycle tall, with a higher starting rate than if a progressive was used,” he explains.

“Motocross riders, on the other hand, like a more progressive spring as the rear-end will ‘stand up’ under high-load situations with increasing force and give them more bottoming resistance off big jumps.”

Teknik is now working on developing springs for other no-linkage bikes, such as Husabergs and BMWs, as well as ATV applications. And, given the recent interest from race teams in Europe and America, they’re exploring export options, too.

ACCORDING TO THE PROs

While Teknik has struggled to market the idea to the KTM dealer network, the tapered wire springs have kicked a few goals. We spoke to Motorex KTM MX/SX young gun Tye Simmonds, his mechanic Ken Wheeler and Motorex KTM Off-Road’s Ben Grabham about their experience with the product.

 

“It makes the bike a lot easier to ride with confidence.” Tye Simmonds

 

KEN WHEELER:

“I found that when I was trying different spring rates, it was more than likely it was a different brand spring. And because everyone seems to wind their springs a different way, it was like putting a different linkage on the bike every time I was changing the spring.

“The good thing about the Teknik springs is that there’s a range, and the rate gets progressively firmer as you move from the start to the end of the travel – much like a linkage ratio curve.

“This helps make it a lot easier to tune the bike. We found the spring offered improved bottoming resistance when we first started using it on Tye’s bike at last year’s Super X, but the biggest gains we found were on motocross tracks.

“A KTM is quite a good thing under acceleration, but in off-throttle situations, where the front of the bike is loaded and the weight comes off the rear-end, KTMs with standard suspension tend to kick around a lot. The Teknik tapered-wire springs made the bike much more stable and predictable in these situations.”

TYE SIMMONDS:

“Ken is always bringing me new things to try, and as soon as I tried the tapered-wire progressive spring, I thought the thing was awesome and I’ve used it ever since – in the Super X, the MX Nats and the World Junior MX Championships over in New Zealand.

“I’ve found it tracks a lot better under acceleration, but the biggest difference is how stable it makes the bike through braking bumps. On small, chattery braking bumps and big ones – like the sand over at WA’s Wanneroo track – the back-end behaves much better. It gave me some small improvements with lap times, but it makes the bike a lot easier to ride with confidence. Now that I’ve stepped up the 450SX-F, I’m noticing the difference even more.”

BEN GRABHAM:

“I first tested the Teknik tapered-wire spring back-to-back with some conventional progressive springs before this year’s Finke Desert Race. Obviously, the shock needs to be re-valved when you fit the Race spring – it’s a death-trap if you don’t – but the tapered spring was noticeably softer in that initial part of the stroke and felt really good over the high-speed chop.

“What surprised me was that it still worked well on the big bumps. So it was great to have a shock that was softer initially and still resisted bottoming better than other shocks. It was better on acceleration and under brakes, and that’s why I decided to run it in the race. I plan to run it in the Baja 1000 later this year, too.

“I can understand why the motocross guys have also found benefits with the thing. But, to be honest, I’ve struggled to find a setting that gives me the same improvements on the slower speed tracks at most AORC rounds. I think it has a lot of potential and I’d like to do some more testing. I know Teknik’s got a less progressive tapered spring now available.”
 

Replacing your Bike's Graphics

Your bike's graphics say a lot about your personality. Your sense of style, your sponsors, your likes and how you treat your bike.

Click to download orginal article in Transmoto Magazine or scroll down to the bottom.
Courtesy of Transmoto Magazine.


HOW TO REPLACE YOUR BIKE’S GRAPHICS

...without it looking like the contact vinyl on your high school history book.

There’s no more cost-effective way to improve your bike’s looks than to replace the graphics. Think of it like getting a haircut – some do it to look like Leonardo DiCaprio, others to just appear respectable. But either way, it’s a job that just needs to happen every now and then.

After a year or two, most graphic kits start to peel around the edges, fade from the sun or have holes worn in them. Although it mightn’t look like it, they actually get a pretty serious workout between your knees as you hang on to your bike for dear life while you approach that triple.

Fortunately, new graphics kits are relatively cheap, allowing you to add a bit of customised flair to your bike, and they are pretty straight-forward to replace with the right technique. There are plenty of off-the-shelf kits out there for most bikes. Aftermarket kits are fairly cheap, whereas genuine kits tend to be a bit better. Or better still, a few Aussie graphics manufacturers offer custom kits that allow you to fit as many sponsors logos or smartarse slogans as you please.

Over the next three pages, Nick Dole from Teknik Motorsport explains how to do it the easiest way.


DIY WORKSHOP

IN THE SERIES…

JUN ISSUE 32. HEAD BEARINGS - No more shaking like Elvis...

AUG ISSUE 34. MUFFLER REPACKING - Because stealth is better...

SEPT ISSUE 35. VALVE ADJUSTMENT - Keep that thumper pumping.

OCT ISSUE 36. 4T PISTON CHANGE - Four-strokes get tired, too.

NOV ISSUE 37. TIMING CHAIN - Change it the right way.

DEC ISSUE 38. SHOCK SPRINGS - Get that bounce dialled.

JAN ISSUE 39. REPLACING WORN GRAPHICS - Bring back that new bike feel...


 

TOOLS YOU’LL NEED

  • Squeegee
  • Heat gun
  • Razor blade

 

COST OF REPLACING YOUR BIKE'S GRAPHICS

  • Labour: 1 hour
  • Graphics: $100-$220

 

GIVE YOUR BIKE A GOOD WASH

Before you start on the graphics, give your bike a thorough wash. Dirt and grit falling into the new graphics adhesive will create high points, weaken the adhesive and eventually wear through. When clean, leave the plastics out in the sun, then start at one corner and begin peeling. If it’s cold, give the old graphics a quick hit with the heat gun before peeling.

CLEAN THE BARE PLASTICS

You can do this job with the plastics on or off. With the plastics on, it’s easier to keep things steady, but we stripped the plastics off for better photo angles. If you were careful about how you peeled the graphics off, there will be little, if any, glue left on the plastics. Whatever glue is left behind should be hit with special glue and adhesive remover or soaked in eucalyptus oil, then covered in glad wrap to soak.

GET A CORNER STARTED

With the plastics prepped, hold the new graphic up to the panel you’re about to apply it to and see how everything lines up. Ideally, you will have a consistent 2-3mm gap between the edge of the graphic and the plastic, with all holes fully aligned. Give the panel another wipe to remove any airborne dust or dirt particles. Then start with the longest flat edge of the graphic and peel back about half of the backing paper. Line it up with any holes or edges and get it started.

USE HEAT TO YOUR ADVANTAGE

With one edge started, grab your squeegee and heat gun and start slowly plying more and more of the graphic on. Hold the loose graphic away from the bike with one hand, then use the heat gun in the other to warm up an area about 100mm wide. Then swap the heat gun for the squeegee and start plying the graphic on, directing the flow of traffic by pulling the loose part of the graphic in the right direction.

STRETCH & MANIPULATE

Don’t be afraid to get rough with the graphics. It’s a bit like pulling your little brother’s hair when you were a kid - pull hard enough and you’ll get it to behave like you want it to. Use plenty of heat and figure out exactly how you need a section to go. You can expect quality graphics to stretch by about 15-20% of their length.

GET RID OF BUBBLES

Bubbles are just trapped air, and bad news. This is where graphics will start to peel from and they can burst, leaving holes. Luckily, the glue on decent quality graphics will give you at least four or five goes at peeling the graphic back and starting again. First try and use your squeegee to push any bubbles to the edge, and if that doesn’t work, peel it back and start again. A small prick with a pin (and we’re not talking about your mate, Shorty, here) will allow you to smooth the most stubborn of bubbles out.

TIPS AND TRICKS WHEN APPLYING GRAPHICS TO YOUR BIKE

  • When applying graphics, heat is everything. A heat gun is best, but a decent hair dryer or a bloody hot, sunny day might also do the trick. If the wife’s out, you could try microwaving ‘em.
  • If you want a quality heat gun that will last more than a couple of years, get a Bosch. Everything else pales in comparison.
  • Make sure all of the backing comes off the graphics completely. A few little bits of paper left on will prevent the glue from setting, causing the graphics to lift.

 

WORK THE EDGES

The edges are where graphics start to peel from and begin to look daggy, so pay extra attention to make sure you push the graphics down hard to give the glue the best chance of doing its thing. Use the heat gun to warm them up, then squeegee them down hard. Quality graphics are remarkably flexible, so you can get away with a lot in terms of creases or stretching with a bit of heat and persistence.

TRIM LOOSE EDGES

Any edges that overhang the plastic will allow water to work its way under the graphics, lifting them off. To prevent this, grab a craft knife and trim any overhanging edges. This includes around any bolt holes. With the edges trimmed, the only thing left to do is wait for the glue to set. This usually takes a couple of days if you want your new graphics to really last, so resist the temptation to ride that shiny lookin’ thing.

 

Upgrading Kawasaki's KX450F

It's back and better than ever. But it can be even betterer.

Click to download original article in Transmoto Magazine or scroll down to the bottom.
Courtesy of Transmoto Magazine.


MEET THE FITTER, FASTER, LEANER KAWASAKI T-BUILD KX450F

With handpicked performance upgrades, the standard 2011 KX450F has drifted into obscurity. Meet the fitter, faster, leaner T-Build KX450F.

Any bike I’ve raced in the past, whether it’s been a two- or four-stroke, has always been modified in three key areas first. Generally, I’ll stick to upgrading the suspension, brakes and exhaust before touching the engine’s internals. Covering those three aspects first is essential to building a fast bike.

An overpowered engine bolted into a poorly performing chassis is an express ticket to the back of the pack. Transmoto’s T-Build KX450F project is based on that exact philosophy.

As reported in the July issue, I tested a standard 2011 KX450F with several hours on the meter. That let me understand both the bike’s strengths and weaknesses, and what was required to transform it into a nationally competitive race weapon. Armed with a handpicked shopping list of performance parts, the KX450F evolved into a finely tuned tool. You won’t find any unnecessary bling. There’s no titanium exhaust system and no anodised engine plugs. Clutch, mapping and pipe aside, the engine itself has been left completely untouched. It’s gone from standard to purpose-built moto-weapon without any unnecessary bolt-on bits, and it’s a real keeper.

THE PROCESS: EVOLVING KAWASAKI'S KX450F INTO A FINELY TUNED TOOL

When it comes to suspension, knowing your weight, riding style, riding experience and preferences, all helps suspension tuners get it right the first time. Teknik Motorsport was in charge of the suspension upgrade on our KX450F and can do anything from the bare essential upgrade to an A-Kit package. Having provided vital feedback from earlier testing, the standard Kayaba fork and shock were returned to Transmoto with slightly heavier springs, front and rear. Internally, Teknik installed their T-Valve kits for better oil flow on the compression stroke and tailored the settings. An SDI linkage kit replaces the OEM unit to create a more linear rising rate. It also lowers the bike’s rear-end slightly to increase straight-line stability.

To sharpen the front-end’s turning characteristics, we’ve bolted on a set of billet aluminum Applied Racing triple clamps with a 22mm offset. The front Kevlar-braided brakeline has been replaced with an Artrax steel-braided line to increase feel and pad pressure, and a huge 270mm Artrax oversize disc kit amplifies the KX450F’s stopping power.

While we could’ve kept the Kawi’s standard ECU, an Aussie-made Vortex X10 releases untapped potential inside the 450s ‘safe’ operating parameters. The X10’s ability to make the best of every horsepower and boost throttle response also comes with 10 preloaded maps for a variety of conditions.

The standard exhaust, while doing a good job of keeping noise emissions to a low 94dB, is replaced with an equally quiet Yoshimura RS-4 system to let the engine breathe. However, I’ve opted for the cost-effective stainless/aluminum system, not titanium, for its durability and better heat dissipation properties.

On top of improved throttle response, boosted braking performance and more predictable suspension in super-rough conditions, I’ve also improved the bike’s ergonomics. Artrax 50mm wide footpegs replace the standard arch-cutters to provide more grip and stability for my size 12 boots. A Blackbird tall seat foam and gripper seatcover replace the woefully soft standard unit, and I’ve bolted on a preferred set of 996 Renthal Twin-Wall handlebars with dual-compound Kevlar grips.

For the 450’s drivetrain, there’s a complete Hinson BilletProof system to provide more oil through the clutch pack and handle the extra abuse. By bathing the clutch in more oil and manufactured to tighter tolerances, the Hinson unit provides better feel, especially at high temperatures, and a longer lasting clutch.

 

UPGRADES

SUSPENSION

CHASSIS

Teknik T-Valve kitted forks

$588

www.teknikracing.com.au

Applied Racing 22mm offset triple clamps

$459

www.teknikracing.com.au

Teknik T-Valve kitted shock

$588

www.teknikracing.com.au

Artrax 50mm footpegs

$89.95

www.ficeda.com.au

SDI Linkage Kit

$599

www.teknikracing.com.au

EXHAUST

ENGINE

Yoshimura RS-4 stainless/aluminum system

$649

www.serco.com.au

Vortex X10 ECU

$769.00

www.vortexcdi.com

ERGONOMICS & CONTROLS

Uni Filter ProComp 2

$65

www.ficeda.com.au

Renthal Twin-Wall handlebars

$169.95

www.cassons.com.au

GEARBOX

Renthal Kevlar dual-compound grips

$29.95

www.cassons.com.au

Hinson Complete BilletProof

$1295

www.serco.com.au

Blackbird high seat foam

$89.95

www.offroadimports.com.au

GEARING

Blackbird gripper seatcover

$69.95

www.offroadimports.com.au

Renthal 13-tooth front sprocket

$29.95

www.cassons.com.au

ARC folding clutch lever

$89.95

www.lustyindustries.com.au

Renthal 51-tooth rear sprocket

$79.95

www.cassons.com.au

ARC folding brake lever

$89.95

www.lustyindustries.com.au

Regina RX3 520 chain

$129.95

www.cassons.com.au

BODYWORK

BRAKING

SPP graphics

$289.95

www.serco.com.au

Artrax 270mm front brake rotor kit

$199.95

www.ficeda.com.au

Acerbis complete plastics kit

$249.95

www.offroadimports.com.au

Artrax braided brakeline

$89.95

www.ficeda.com.au

Acerbis X-Force handguards

$59.95

www.offroadimports.com.au

Bendix brake pads front & rear

$57 (each)

www.ficeda.com.au

TOTAL: $6885.25

 

Check www.transmoto.com.au for more suspension upgrade options and their costs.

 

THE RESULT: TRANSMOTO’S FITTER, FASTER, LEANER T-BUILD KX450F

While it’s been more than a month between test rides, Transmoto’s completed T-Build KX450F couldn’t be any closer to the objective I first set out to achieve. Firmer suspension settings have turned the previously plush ride into a race-focused balance between soaking heavy hits, plushness and stability. Where I was earlier concerned with the back-end stepping out or the front-end tucking through tight corners, I’m now confident the bike won’t do anything silly at high speed. The benefits from the extra feel and predictability are massive. Swapping the standard 24mm offset triple clamps for the Applied 22mm offset clamps was a standout upgrade. The front-end is more planted through turns and the bike doesn’t want to stand up at the apex. What’s more, turning the 450 is now so much easier. On top of the offset change in the triple clamps, the SDI linkage delivers a smoother rising rate and shock action. It’s made the back-end more planted and track straighter, delivering more drive into the ground and soaking up a great deal of harshness.

As well as sounding ultra-horn, Yoshimura’s RS-4 exhaust system has let the engine breathe and, as a result, there’s slightly more power on tap. Coupled with the Vortex X10, the throttle response is instant and the engine revs without restraint to a higher limit. There isn’t a great deal more horsepower, but the engine seems to revel in the ECU’s ability to spread it out across the range – exactly what I was after. Vortex’s pre-installed slippery track map also works well to dull the power delivery around greasy race circuits.

Bumping the standard gearing from 13/50 to 13/51 meant I could easily pull a gear higher with the added torque from the exhaust/ECU upgrades. The Hinson clutch (which comes with its own springs) appears to have made the clutch-pull slightly stiffer, but its feel and take-up are noticeably more consistent.

Upgrading the standard ergos to Renthal Twin-Wall handlebars and grips, ARC levers, and larger Blackbird seat and Artrax footpegs, all made the 450 more comfortable to ride for my larger frame. I’ve always found standard handlebars too narrow and the seat too low. Artrax’s 270mm oversized front disc kit, together with their steel-braided front brakeline, is night and day better than the standard brake system. Not only is there now gobfuls of braking power, there’s also a lot more feel at the lever.

Underlying this T-Build project has been the notion that a small number of key upgrades will produce the most significant improvements. And that’s exactly what we’ve achieved. I couldn’t have been more stoked with the 450s performance in its final trim. And the funny thing is, many of the upgrades we’ve done to this 2011 bike have now been integrated into the just-released 2012 model. Read on for our ride impression on the new 450, and a comparo between it and our T-Build.

WHEELS

Michelin Starcross MH3 tyres wrap the standard front and rear rims. They’re suited to a mix of intermediate and hardpack terrain, but also perform well in muddy conditions. Inside the MH3s is a set of Michelin’s Ultra Heavy Duty tubes to reduce the risk of a mid-moto flat. A 270mm oversized front brake kit comes courtesy of Artrax for massive stopping power, while an Artrax steel-braided front brakeline replaces the standard Kevlarbraided one. Bendix brake pads front and rear provide the bite on the discs.

COCKPIT

Alongside the Renthal 996 Twin-Wall handlebars and dual-compound Kevlar grips, there’s a set of Acerbis X-Force handguards to protect the digits from roost and rocks. They come with an extra protection flap, which I’ve left off to reduce bulk. ARC folding brake and clutch levers replace the buttery-soft standard units.

THE LOOK

An Acerbis complete plastics kit replaces every panel on the bike and they fit like a glove. All you need to do is swap the washers over from old to new. Serco’s SPP graphics department supplied the custom-designed laser-cut Transmoto graphics package, which gives the 450 a real individual personality.

 

“With a handpicked shopping list of performance parts, the KX450F evolved into a finely tuned tool.”

 

DRIVETRAIN

Clutch hardware in most standard dirt bikes struggles to withstand the torture of or national-level racing. To combat this, a Hinson BilletProof clutch has been installed to reduce tolerances between parts and is drilled for improved oil flow through the clutch pack. We run a shorter 13/51 Renthal sprocket combo (standard is 13/50), while a Regina RX3 chain connects the two to put the power to the ground.

ERGOS

Kawasaki’s OEM seat foam turns to mush at around 15 hours of use. Because I wanted more legroom between the seat and the footpegs, I replaced the standard foam with a 20mm taller Blackbird seat and gripper cover. Replacing the Kawi’s standard footpegs is a set of super-sharp oversized 50mm Artrax units. They’re good!

ENGINE

The KXX450F’s standard engine produces just over a 50hp and is particularly strong in the mid-range. I wasn’t after any more power, but spreading it out across the range more effectively was an important objective. To achieve that, we mated a full stainless/aluminum Yoshimura RS-4 exhaust with a Vortex X10 ECU.

SUSPENSION

Along with Teknik Motorsport’s upgrades to the Kayaba fork and shock, there’s an SDI linkage assembly to lower the rear-end slightly and provide a more linear rising rate. While the T-Build’s new suspension only received the bare essential upgrades, Teknik does provide a premium A-Kit service, like that used on factory race bikes, if money is no object or you. Check www.transmoto.com.au for details.

KAWI REBORN

The KX450F has always been predictable and powerful. But after evolving slower than its rivals in recent years, Kawasaki has delivered something special for 2012; with launch control, a slimmer frame and adjustable ergos!

If there weren’t any bike pictures accompanying the PR that read “allnew slimmer chassis, adjustable riding position and upgraded shock absorbers”, you could be mistaken for thinking you were about to be hit with another tasteless dose of Zoo magazine. Which ever way you look at it, we reckon you’re much better off, because Kawasaki’s new 2012 KX450F is ready to please. And, unlike a lingerie model, it’s not just limited to rich ugly dudes.

Through the past half-decade, Kawasaki’s KX450F has been screaming to be top dog in the Open-class pack. It may have racked up some impressive titles around the world during that time, but it’s struggled to keep up with the fast-paced evolution of its competitors. Never suffering from a lack of raw power, the KX450F has, however, struggled to get into and around turns. Which is exactly why a set of 22mm offset triple clamps is always one of the first upgrades any privateer or factory team do to the bike. Not only that, but the KX-F’s ergonomics have been increasingly regarded as old-school and porky.

While the lion’s share of Kawi’s development budget may have gone into the soon-to-be-released 2012 KX250F with its all-new twin injector nozzles, improvements to the 2012 KX450F are certainly significant enough to sever the bike from all past incarnations.

Kawasaki Australia recently held the launch for their new bike at Macarthur Motorcycle Club’s national MX track in Appin, and Transmoto was invited along to see what all the buzz was about.

WHAT’S NEW ON THE 2012 KX450F

Calling the refinements to the 2012 KX450F subtle would be an understatement. It ain’t a ground-up rebuild, but the bike represents a significant departure from its past. Perhaps the biggest improvement to the KX450F is the frame, which is 4mm slimmer than previous model’s. Covering it is a modern and streamlined bodywork package. The new 450 is very much focused on ergonomics that can be better customised to the rider. On the 22mm offset triple clamps, there’s now four handlebar position options that deliver 35mm of movement. Meanwhile, the set of large platform footpegs can now be mounted in two positions: standard or 5mm lower – a move aimed squarely at taller riders or racers who prefer a lower foot position.

Taking holeshot buttons to an electronic level is Kawi’s ingenious Launch Control System. Activated by a button on the handlebar, the subdued engine map limits the rush of power as you dump the clutch to dramatically increase drive off the startline. The temporary ECU map only works in first and second gears; once you hook third, the system reverts back to full power.

Kawasaki’s FI Calibration Kit wasn’t the easiest ECU mapping unit to use, so they’re now offering three pre-programmed maps in the form of DFI couplers (standard, hard and soft). They’re a welcomed addition and can quickly change the engine’s ECU mapping at the track, without delving into the more complex calibration kit.

Inside the engine, a new bridge-box bottom piston with revised skirting results in less friction for quicker response, and new intake cam profiles contribute to a better delivery of power down low. In tune with updated styling, Kawi has given the standard muffler some artistic love. It’s now 60mm shorter but, due to its internal design, still conforms to FIM noise regulations.

To improve shifting and gearbox durability, first gear is now 2.8mm wider, the shifter fork has dropped 0.9mm in length for a quicker action, and they’ve increased the number of engagement dogs and slots from three to four. While the suspension sees minor tweaks for 2012 – improved bottom-out resistance, for one – you can now use an optional tie-rod in the shock linkage (1mm longer than standard) to lower the seat height by 4mm and make the linkage’s rising rate more linear.

DFI COUPLER

Want to liven the KX450F’s engine or numb it down for the conditions? No problem at all. Just connect the hard or soft DFI coupler for instant power delivery changes.

TRIPLE CLAMPS

Every rider prefers a different handlebar position. For 2012, the KX450F’s bar mounts can be fixed in four positions. That’s an impressive 35mm of adjustability.

MUFFLER

New styling also means a new aesthetically pleasing triangular-shaped muffler. It’s 60mm shorter than last year’s, a tad fatter and still meets FIM regulations.

LAUNCH CONTROL

Ground control to Major Tom… Kawasaki’s new electronic ‘holeshot’ device is cleanly integrated into the handlebars. It works a treat, especially with aggressive maps.

BILLY MACKENZIE:

“I prefer an aggressive engine, so when I first went out on the bike I had the powerful hard map DFI coupler plugged in. And it definitely suited this track. Straight away, I felt more comfortable. I really liked the height of the back-end, the slimness of the frame and its lighter, more agile feel. I use the power to drift the back-end around and position the bike in corners, and because of the chassis set-up, I found it really easy to stay in the centre of bike. The ability to change the power via the DFI coupler is cool as you can quickly customise the bike to different track conditions. Being able to adjust the ergos between handlebars and footpegs makes it ideal for a variety of riders, no matter their size and ability. The launch mode definitely has room to improve for Pro racing, but for the majority of riders racing at club level, having that option will help them out of the gate.”

DEAN FERRIS:

“A few things stuck out for me straight away. The new frame is slightly skinnier and makes it easier to grip the bike, especially as I ride standing up a lot. Over the past few years, Kawasaki’s seats have been really soft. Now it seems firmer; making it feel more like the seat on my race bike. And I’m picky about my seat. The three map options for the ECU are really good. In the morning, when the track was very slippery from all the watering, I used the soft plug to calm the engine down. Later in the day, once some ruts had formed, I had a ball on the hard map. Also, starting with the launch control is fantastic. I can’t believe someone hasn’t invented that sort of riding aid earlier, and we’ll be using it during racing for sure. All the changes made to the suspension and chassis make the bike turn-in so much better, so I reckon it’s only going to get harder to improve these bikes a lot in the future.”

DOES THE NEW KX450F FEEL DIFFERENT?

Considering the frame is only 2mm slimmer on each side and the bodywork has been streamlined, it’s made a surprisingly big difference to the feel of the KX450F’s ergos. The cockpit is noticeably slimmer and more compact. Kawasaki may be claiming harder seat foam, but it feels the same as last year’s, albeit brand new, and only time in the saddle will reveal how fast it turns to mush. Despite this, the new seat is actually flatter overall, not only making it easier to move around on, but also making you feel more in control from above the machine. And compared to older models, there’s no ugly overlapping bodywork plastic to snag your boots or kneebraces. I moved the footpegs down a notch to provide extra leg space and instantly felt more comfortable. Long gone is the cumbersome big-bike feeling that plagued the older KX-Fs.

HAS THE TWEAKED CHASSIS IMPROVED THE HANDLING?

The KX450F has always been super-stable on rough tracks. While it preferred railing long, fast, sweeping corners, the same couldn’t be said for tighter turns. The changes made to lessen the rigidity in the rear linkage, the addition of 22mm triple clamps up front, and the internal fork and shock refinements, have combined to produce a 450 that’s nimble on its feet while retaining plenty of overall stability. Simply put, if the 22mm offset triple clamps were the only mod they made for 2012, it’d do the trick.

DFI COUPLERS – GIMMICK OR FOR REAL?

Suzuki was the first manufacturer to offer the DFI coupler idea to quickly change the ECU’s power delivery for varying conditions. KTM and Yamaha both offer tuning tools to achieve a similar result, although they’re not quite as simple to use. No matter how trackside EFI tuning is offered, there’s nothing better than taking advantage of all that technology between your legs. After several motos using the standard coupler (or map), we installed the hard coupler (more responsive map) and it made the engine so responsive and aggressive, that it was almost unusable around the hardpack Appin track. Obviously, it’s designed for loamy tracks. For slippery conditions, the soft map works really well at de-tuning the engine. To get that sort of result previously, you had to invest in an aftermarket ECU.

DOES LAUNCH CONTROL WORK?

Under real-world use, the handlebaractivated launch control mode isn’t just a cool gadget; it’s a major benefit. While it will never replace perfect starting technique, activating the launch map helps to smooth out the power delivery in first and second gears. It’s designed to maximise drive and limit wheelstands.

Timing starts with an iPhone is less than scientific, but from the dozen starts performed, my racing background preferred starting without the launch mode activated. However, once the hard coupler was connected to the ECU, the launch mode had a more noticeable effect in controlling the Kawi’s eruption of power. Like the prolific spread of holeshot buttons over the past decade, I’d expect Kawi’s launch mode will follow a similar trend. It’s perfect for a large chunk of the market. And for the Pros, it means a slight tweak in their starting routine to take advantage of the additional engine – and traction – control.

 

“Never suffering from a lack of raw power, the KX450F has, however, struggled to get into and around turns.”

 

2011 VS 2012 KX450F

Since Kawasaki’s release of the 2012 KX450F, we’ve been keen to put our T-Build 2011 KX450F up against it. Even though Kawasaki has clearly stepped in the right direction with their latest 450, you might argue that pitting a race-ready bike against the latest-generation stocker isn’t really comparing apples with apples. But Kawi’s 2012 450 is worthy of butting heads with modified older-gen model.

To do this, we took both bikes to Macarthur Park’s practice track and rode them back-to-back. Updated suspension, the addition of 22mm offset clamps, improved ergos and a slimmed-down frame for the latest 450 certainly doesn’t relegate the 2011 450 to solely a spare parts bike. Knowing the 2011 KX-F’s weaknesses in ergonomics, braking and steering – the same areas the KX450F design team has now addressed – helped us to evolve the 2011 KX-F into a very good machine. We’ve upgraded it to handle rough tracks, turn better with the 22mm offset triple clamps and given the engine a better spread of power with an aftermarket ECU and exhaust. The only two areas we couldn’t modify were knocking 4mm off the width of the frame or adding the new bodywork.

As much as I’m in awe of Kawasaki’s latest offering, testing both machines in the same conditions made me realise how much better a personalised bike can really be. While I still favour the slimmer frame and bodywork on the latest 450, mods made to the chassis, braking and power delivery in our T-Build 450 won my vote. It’s faster, better-handling and more comfortable to ride.

So, what does this mean for Kawi owners looking to upgrade or racers purchasing a run-out special? Owning a 2012 KX450F will certainly put a smile on your face, as the complete package is the best Kawi has produced in years. But even with selected mods from our T-Build project, a well-sorted 2011 450 will make you just as competitive on the track, albeit without the ease of ECU map changes.

SPECS – 2012 KX450F

RRP (incl GST, excl pre-delivery)

$11,999

Distributor

www.kawasaki.com.au

Warranty

No warranty

ENGINE

Capacity

449.0cc

Bore x Stroke

96.0 x 62.1mm

Cooling

Water-cooled

Engine Type

Single-cylinder four-stroke, DOHC

Compression Ratio

12.5:1

Transmission

5-speed

Final Gearing

13/50

Clutch

Wet, multi-plate, cable-operated

Fuel Capacity

7.0 litres

Carburetor

43mm Keihin EFI

SUSPENSION

Fork

Kayaba –48mm USD twin-cartridge

Shock

Kayaba Uni-Trak

GEOMETRY

Claimed Weight (fuel & fluids)

113.5kg

Wheelbase

1480mm

Seat Height

960mm

RUNNING GEAR

Handlebars

Renthal 971

Front Tyre (as tested)

Bridgestone Motocross M403

Rear Tyre (as tested)

Bridgestone Motocross M404

BRAKES

Front

Nissin – 250mm disc

Rear

Nissin – 240mm disc

 

MORE ONLINE…

Head to www.transmoto.com.au for more images and video from the launch, and interviews with Team Monster Energy Kawasaki’s Dean Ferris and Kawasaki Australia’s Rudi Baker.