Owners Manual Öhlins shock absorbers, MX/ENDURO/OFF ROAD Including: Safety Tuning the suspension Design features Function Basic adjustments Fine tuning Photo: Ray Archer Inspection, maintenance 1 Safety signals Important information concerning safety is distinguished in this manual by the following notations: Introduction All of Öhlins advanced suspension products are adepted to the brand and model. This means that length, travel springaction and damping characteristics, are tested individually just for the motorcycle that you have decided to fit with Öhlins suspension. WARNING! 1. Installing a shock absorber, that is not approved by the vehicle manufacturer, may affect the stability of your vehicle. Öhlins Racing AB cannot be held responsible for any personal injury or damage whatsoever that may occur after fitting the shock absorber. Contact an Öhlins 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 shock absorber kit. If you have any questions regarding proper installation procedures, contact an Öhlins dealer or other qualified person. 3. The vehicle service manual must be referred to when installing the Öhlins shock absorber 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. Before installation Öhlins Racing AB can not be held responsible for any damage whatsoever to shock absorber 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. CAUTION! Caution indicates that special precautions must be taken to avoid damage to the suspension. Contents Saftey signals ................................................ 2 Tuning the suspension ................................... 3 Design ........................................................... 3 Function ........................................................ 4 Compression damping ................................ 4 Rebound damping ....................................... 4 Settings ......................................................... 5 Basic settings .............................................. 5 Setting the spring preload ............................. 5 Measuring .................................................... 5 Recommendation ........................................ 5 Adjusting ...................................................... 6 Front fork spring .......................................... 6 Setting the shock absorber lenght ................. 6 Setting the damping ...................................... 7 Setting your motocycle .................................. 8 Start with rebound damping ........................ 8 Compression damping ................................ 8 Inspection and maintenance ......................... 9 NOTE! This indicates information that is of importance with regard to procedures. NOTE Öhlins 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 Öhlins dealer if you have any questions with regard to the contents of the manual. © Öhlins Racing AB. All rights reserved. Any reprinting or unauthorized use without the written permission of Öhlins Racing AB is prohibited. Printed in Sweden. 2 1. Design principles Gas Oil Oil Gas 2. Spring preloading Mechanical adjustment 3. Adjustment of shock absorber length 1. External reservoir with hose connection 2. External piggyback reservoir 3. Internal gas reservoir 4. Twin piston shock absorber Oil Separating piston Shock absorber piston 1 2 3 4 Twin piston Gas C-spanner Adjustment nut - + Tuning the suspension Motorcycle road holding qualities All motorcycles are designed with a suspension geometry that includes height and fork angle. The changing of components can affect this and it is therefore essential that both the rear and the front ends match each other. Changing to Öhlins suspension gives optimum performance only when both the front fork and the rear suspension interact properly. It is of the greatest importance that the front and rear loaded height are within the specified values. In the mounting instruction, see section: Setting the spring preload. Design Most of the Öhlins shock absorbers are of the De Carbon type (Fig.1). The fluid is put under gas pressure and the gas and the fluid are kept apart by a separating piston. The separating piston is often fitted in a separate fluid chamber, connected by hose (1), or fixed direct on top of the shock absorber (piggyback) (2). There are also cases where everything is fitted inside the main shock absorber (internal gas reservoir) (3). The most advanced shock absorber has twin pistons. This ensures position sensitive damping in relation to the degree of compression. One of the pistons is active throughout the entire lenght of stroke, while the second piston begins to work in the event of powerful compression of the shock absorber (4) Pressurization of the fluid is made with nitrogen. The pressurization prevents cavitation of the fluid and the shock absorbing action is therefore more even. The external fluid chambers also contribute to better cooling of the fluid, giving longer service life for both the fluid and components. Öhlins shock absorbers have integrated temperature compensation. As the temperature increases and the fluid flows more easily the flow is controlled accordingly. The shock absorbing effect is therefore independent of the temperature. The more advanced models permit individual adjustment of compression damping and rebound damping. Öhlins shock absorbers provide the possibility for adjustment, making them adaptable to most motorcycles, riders and ranges of use. All of the shock absorbers have adjustable preloading of the spring action (Fig.2). A few models have an adjustable end eye, making it possible to alter the lenght of the shock absorber 12mm (Fig.3). 3 4. Flow through needle valve 5. Piston with apertures 6. Shims stack Stop washer 7. Flow through piston Shims stack Compression flow Piston Rebound flow Function The function, in principle, is that fluid is forced through needle valves at a low rate of flow (Fig.4) and through a number of apertures in the piston (Fig.5) at a high rate of flow. The flow through these apertures is regulated by shims (thin steel washers) that at high pressure are deflected to open for the fluid. On most models the needle valves can be set individually. By altering the size of the shims-stack (Fig.6) (ie, number, thickness, diameter) the characteristics of the damping action can be varied (this shall only be done by Öhlins authorized service workshops). Compression damping When movement of the motorcycle causes compression in the shock absorber, the fluid flows through the needle valve (combined compression and return valve) in the piston rod. If velocity of the piston is high, ie, in the case of rapid compression, this will not be sufficient and consequently the shims underneath the piston will open to allow a greater rate of flow (Fig.7). The fluid that is displaced by the volume of the piston rod is forced into the external fluid chamber via a separate compression valve. The separating piston is displaced, thus increasing the gas pressure. Rebound damping When the spring presses the shock absorber out again, the fluid flows back through the needle valve in the piston rod. The fluid flowing into the chamber is forced by the pressure of the gas back into the shock absorber via a separate nonreturn valve. If velocity of the piston is high, the shims on top of the piston will also open to allow the fluid to flow though (Fig.7). 4 F1 F2 F3 R1 R2 R3 Bike on a stand. Bike on the ground. Bike with rider on. Settings Basic settings Always ensure that the basic setting made by Öhlins is correct. It is adapted to the make and model (in its original state) and for a rider of average weight. Setting the spring preload 1. Measuring: Preload on the spring/springs is very important, because it affects the height of the motorcycle and the fork angle. Consequently, handling characteristics can be changed, even negatively. Proceed as follows (it will be much easier if done by two persons): · Place the motorcycle on a stand, so the front fork and the rear end are in fully extended position. · Measure the distance, eg, from the lower edge of the rear mudguard or from a point marked by a piece of tape, immediately above the rear wheel axle, to the wheel axle (R1). · Make a similar measurement on the front axle, e.g., from the bottom of the upper fork crown to the front wheel axle (F1). · Allow the motorcycle (without rider) to apply load on the springs and repeat the measuring procedure (R2, F2). · Then take the same measurements with the rider and equipment on the motorcycle (R3, F3). It is important that the rider has a correct riding posture, so that the weight is balanced on the front and rear wheel in the same way as when riding. Recommendations: The difference should not deviate from the following sizes, if no other recommended settings are given in the Mounting instructions: Free sag: (R1-R2), (F1-F2) Rear: MX/Off-Road 30±5 mm Front: MX/Off-Road 30±5 mm Ride height: (R1-R3), (F1-F3) Rear: MX 100±5 mm Off Road 30% of the total stroke Front: MX/Off-Road 80±5 mm 5 WARNING Incorrect spring action can give a fork angle that is too steep or too flat.This in turn will give a tendency for oversteering or understeering, which could seriously affect the handling characteristics of the motorcycle. The original setting of the shock absorber, when delivered from Öhlins, should always be a base when the settings are changed by use of the adjustment devices. 8. Spring preloading 9. Front spring kit 10. Adjustable end eye WARNING! If the shock absorber has an adjustable end eye/bracket, this must not be treaded out more than that one groove is fully visible beneath the lock nut. Make sure that the lock nut is tightened after adjustment. Groove Mechanical preloading adjustment Setting the shock absorber length 2. Adjusting Adjust the preload with the rings on the shock absorber. Hold the upper ring and adjust the lower one to the desired position (Fig.8). Then lock with the upper ring. Front fork springs To optimize the road holding qualities of a motorcycle the front fork must match the rear suspension. Öhlins springs are available for a large number of motorcycles (Fig.9). These, in combination with Öhlins shock absorbers, contribute to superior road holding qualities. The original make of springs should be used if there are none of our springs in the recommendation table. However, they must be in good condition and not fatigued. Remember to change the fluid in the front fork at least once every year. We recommend Öhlins front fork oil. Sensitivity of the steering can be adjusted by altering the length of the shock absorber, without affecting other characteristics. The length is adjusted using two nuts down and the treaded clevis at the end of the piston rod. The shock absorber can be adjusted up to 12 mm. The length may never be altered more than to where the groove that is cut in the thread becomes just visible (Fig.10). NOTE! If ride height is higher than recommended, softer spring/springs must be used. If ride height is lower than recommended, harder spring/springs must be used. Contact your Öhlins dealer for advice. WARNING! It is important that the recommendation table is followed for new front springs. If there are no recommended front springs you must ensure that the existing springs are in good condition. Neglecting to check the front springs could seriously affect the handling qualities of the motorcycle 6 11. Adjustment of rebound damping 12. Adjustment of compression damping 13. High and low speed compression damping adjusters High speed + - + + + = more damping = less damping Low speed + - Setting the damping The adjusting possibilities of Öhlins shock absorbers facilitate fine setting. You can optimize adjustments to suit your own weight and equipment, your individual way of riding and the condition of the road. To be able to improve the road holding qualities it is of the utmost importance that you fully understand the functioning of the shock absorbers. Then you can learn by trial and error how they affect the motorcycle. Depending on the model there are adjustments for rebound damping, compression damping and adjustment of the length of the shock absorber. Damping is set with knob ...