Owner`s Manual
Contents
1. absorbers at the same time Start with the rear shock absorber then the centre and for the ultimate results also the ski shock absorbers in the front Basic set up The Ohlins shock absorbers are intended to be a bolt on accessory and have very carefully tested settings You can fine tune the shock absorber with the adjusters You can optimise the shock absorber for your weight riding style and the riding conditions Note Always make sure that the basic setting made by Ohlins is intact It is adapted to the specific make and model Always begin with the basic settings recommended by Ohlins Always make notes adjust in small steps and make only one adjustment at a time Adjustments should be made with two steps clicks turn two way compression damping at a time Most Ohlins shock absorbers for snowmobile are equipped with adjusters for spring preload compression and rebound damping Due to limited space in some vehicles it is not possible to have all adjusters in certain models The three adjusters mentioned above will be discussed in the following chapters A deeper understanding for the different types of adjustments will give you a good knowledge of how you can get better performance from your Ohlins shock absorber e Spring preload when adjusting the spring preload you move the spring seat This will lower or raise the ride height e Compression damping controls the energy absorption when the shock absorber2. is being compressed thus controls how easy the shock absorber compresses when you hit a bump e Rebound damping controls the energy absorption when the shock absorber is being extended and thus controls how fast the shock absorber returns to its normal position after being compressed When adjusting the spring preload you move the spring seat This will decrease or increase the initial spring force which will lower or raise the vehicle rear ride height Spring preload is fundamental for the function of the suspension If the preload is incorrectly set any other adjustments to the shock absorber will not help to get the intended performance from the suspension Ohlins shock absorbers are delivered with the spring preload carefully set for a good balance in the vehicle with a 80 kg or 175 Ib rider The spring preload affects the ride height which on a snowmobile is the same as the share of the total snowmobile weight for each shock absorber to handle This means that it affects the balance and performance of the snowmobile Increasing the spring preload does not make the shock absorber stiffer other than the initial force to compress the suspension from fully extended position Since the suspension should be compressed as soon as you sit on the snowmobile the suspension will not be stiffer after increasing the preload only higher Within reasonable limits the spring preload does not affect bottoming The spring stif
3. H Ride height T H 12 If your snowmobile is equipped with rebound and compression damping the damping is set with knobs and or screws with a normal right hand thread By turning them clockwise the damping action increases and by turning them counter clockwise it will be reduced Most of the adjusters have definite positions with a noticeable click which makes it easy to count to the right setting Rebound damping adjuster with knob Note If you can not feel the clicks on the rebound knob the shock absorber must be inspected by an authorized Ohlins Service Centre It could be due to low gas pressure or lack of oil Rebound damping adjuster with screw Compression damping adjuster with screw Compression damping adjuster with knob 13 High and Low speed Some models called PRX have separate adjusters for high and low speed compression The low speed compression is adjusted in 25 steps The high speed adjuster has a wide range without steps The compression damping affects the energy absorption during compression and thus the force needed to compress the suspension More compression damping will make the suspension firmer and make the vehicle run a little bit higher On PRX shock absorbers the X stands for high and low speed compression adjuster e Low speed circuit More damping will make the ride firmer and higher e High speed circuit
4. More damping gives a firmer ride and more resistance against bottoming The rebound damping affects the energy absorption during rebound and thus the force needed to extend the shock absorber More rebound damping will make the extension slower and vice versa The external rebound adjustment actually also affects the compression damping by the ratio of approximately 90 rebound damping and 10 compression damping Note The damping forces are related to the speed between the shock absorber piston and the shock absorber body The damping forces do not vary with the position of the piston inside the shock absorber High and Low speed Compression damping High speed Hexagon screw Low speed Slotted centre screw 14 Note Always begin with the basic settings recommended by Ohlins Always make notes adjust in small steps and make only one adjustment at a time Adjustments should be made with two steps clicks 2 turn two way compression damping at a time Setting Rebound and Compression By using the adjustment possibilities you can test by trial and error and learn how they affect your snowmobile Always begin by test riding the snowmobile with all adjustments at their basic setting Choose a short run of varying character i e long and sharp bends hard and soft bumps Keep to the same run and adjust only one setting at a time Increase Rebound damping if the suspension feels e Unsta
5. Shock Absorber for snowmobile Owner s Manual It was the 1970 s a young man named Kenth Ohlin spent most of his spare time pursuing his favourite sport motocross A careful observer Kenth s attention was continually drawn to one specific detail motocross bikes had more engine power 4 N than their suspension could handle PN It was not long before Kenth realised that better performance could be achieved by improved wheel suspension N Ohlins Racing was established in 1976 and just two years later the company won its first 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 this 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
6. alve The fluid flowing into the chamber is forced by the gas pressure back into the shock absorber via a separate non return valve If the piston velocity is high the shims on top of the piston will also open to allow the fluid to flow through Stop washer Shim stack Compression Snowmobile traction qualities Most of the snowmobiles have a suspension with four shock absorbers two in the front one in the centre and one in the rear Each shock absorber with its spring will distribute the weight of the snowmobile to the ground and can be seen as a leg Since it is enough with three contact points or legs to carry the weight of the snowmobile without tipping a fourth leg means the whole balance in the vehicle will change with very small adjustments Think about it as adding a fourth leg in the centre of a three legged stool If this centre leg is just a little bit too long one of the other legs will loose contact with the ground On a snowmobile this example could translate into too low ski pressure and lost steering ability if there is too much spring preload on the centre shock for instance Changing to Ohlins suspension gives optimum performance only when both the front and the rear suspensions interact properly Start from the rear The suspension on your snowmobile can be divided into three parts front centre and rear suspension It is advisable to start from the rear if you do not want to change all shock
7. and centre Take the snowmobile for a test ride Choose a short run of varying character i e both long and sharp bends with varying bumps Stick to the same run and make only one adjustment at a time Do you experience that any of the following behaviours are exaggerated e _ The steering requires a lot of effort e The snowmobile front end feels nervous and it is difficult to hold a straight line A Warning Too much ski pressure and or no toe out will cause the sled to dart to each side you will feel unsafe on straights Check that the skis are toe out according to the vehicle manual One of the causes for these behaviours could be that the front and rear shock absorbers take too much of the vehicle weight which is the same as the centre shock absorber taking too little of the vehicle weight Since the rear ride height is already decided by the rear spring preload only the front and centre shock absorber spring preload remain to adjust Try either of these changes Increase the spring preload on the centre shock absorber in 2 mm or 2 steps or decrease the spring preload on the front shock absorbers in 3 mm or s steps Do you experience that any of the following behaviours are exaggerated The snowmobile under steers wants to go straight instead of turning low ski grip The snowmobile pitches from front to rear fig 17 The inner ski lifts when the snowmobile is accelerated out of corne
8. ble Loose e Bouncy Start with the rebound damping If the snowmobile feels unstable loose and rather bouncy then the rebound damping should be increased Begin by turning the adjuster knob 2 steps clicks Test run again and adjust one step back if it felt too hard and bumpy If the snowmobile is hard and bumpy especially over a series of bumps then the rebound damping should be reduced Turn 2 steps test run and make necessary correction For original rebound setting see recommended Set up data in the Mounting Instructions Reduce Rebound damping if the suspension feels e Hard Bumpy Compression damping If the snowmobile feels soft has low riding position and a tendency to bottom easily in long dips then the low speed compression damping should be increased Turn clockwise 4 clicks 1 turn and test run again If this was too much then turn back two steps clicks turn If the snowmobile feels harsh and has hard resilience e g over changes in the ground surface hen the high speed compression damping must be reduced Turn the adjuster Y turn at a time Test run and make necessary corrections When you have sufficient feel of the snowmobile you can make further fine adjustments It is feeling and experience that counts Increase Compression damping if the suspension feels soft feels low is bottoming Note Ensure that the springs are properly preloaded before attempting to make any da
9. bnormal noise or the function is irregular or if you notice any leakage from the product please stop the vehicle immediately and return the product to an Ohlins Service Centre Note When working on this product always read the Vehicle Service Manual This Manual should be considered a part of the product and shall therefore accompany the product throughout its life cycle Safety Symbols In this manual mounting instructions and other technical documents important information concerning safety is distinguished by the following symbols A The Safety Alert Symbol means Warning Your safety is involved A 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 M 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 important regarding procedures Introduction Safety Precautions Contents Design Functioning Adjustments General Ride Height Spring Preload Rebound and Compression Setting up the Snowmobile Inspection and Maintenance Most of Ohlins suspensions are a high pressure monotube type The fluid is put under gas pressure and the gas and the fluid are kept apart by a separating piston The piston is usually fitted in an e
10. eck the attachment of the shock absorber to the vehicle 8 Check the hose equipped models for leaks in the hose and inlet plugs 9 Check that the hose is properly attached and will not interfere with anything Recommended Service Intervals Normal use Once a year Racing use Every 20 hours of operation Disposal Discarded Ohlins products should be handed over to an authorized Ohlins Service Centre or distributor for proper disposal Lift the bump rubber and clean the area below Note The Ohlins shock absorber should only be filled with Ohlins Shock Absorber Fluid Contact an Ohlins dealer for advise A Warning Never change gas pressure Special purpose charging equipment and access to nitrogen is required 17 www ohlins com Ohlins Owner s Manual Shock Absorber for Snowmobile Part No 07230 02_3 Issued 2009 06 15 2009 Ohlins Racing AB Your Ohlins retailer hlins Racing AB Box 722 Phone 46 0 8 590 025 00 SE 194 27 Upplands V sby Fax 46 0 8 590 025 80 Sweden www ohlins com
11. ecrease the rear spring preload until you have reached the middle position of the coupling adjuster If you carry heavy luggage or a passenger you must make the adjustments under the same conditions Check Rear Ride Height Torsion Spring Suspension Check the coupling device Make sure the distances x are equal as indicated in figure 9 If the distances are not equal adjust the rear spring preload figure 10 Check the coupling device again Torsion Spring Pro Active Suspension Yamaha Mono Shock Suspension Check the coupling device The distance should Measure the spring with the suspension be as indicated in figure 11 If the distance unloaded and fully extended L1 figure 13 differs adjust the rear spring preload figure 12 Check the coupling device again Measure the spring vehicle on a flat surface with the rider on in full gear L2 L1 L2 Spring sag Recommended spring sag 40 45 mm This will give a correct ride height If you spring sag is gt 45 mm Increase the spring preload figure 14 lt 40 mm Decrease the spring preload figure 14 Yamaha Pro Action Suspension Check the coupling device Make sure the distances x are equal as indicated in figure 15 lf the distances are not equal adjust the rear spring preload figure 16 Check the coupling device again SN IN HEM SE 10 Front
12. fness and the hydraulic damping are the keys to controlling bottoming W gt Free spring length Installed spring length Shock absorber fully extended A B Spring Preload Spring Preload is the difference between the measures A and B Procedure Set the spring preload to the basic settings on the front and centre shock absorbers Also put the limiter straps for the centre shock absorber to the basic setting according to your vehicle service manual Now you can start adjusting the rear shock absorber according to below Then continue with the centre and front shock absorbers if needed Rear ride height and Riding Comfort It is very important that the rear ride height is adjusted correctly Due to the coupling device in the rear suspension the rear ride height and riding comfort are linked together If the ride height is not within the right range the centre and the rear shock absorbers may start working parallel in unwanted situations thus creating a too stiff suspension and a harsh ride Note These adjustments should be carried out on a flat surface The most correct settings are performed indoors when the snowmobile is thawed out warmed Recommended Rear Ride Height When you sit on the snowmobile in riding position wearing all your riding gear we recommend the coupling adjuster free play to be equal in both directions assuming that the coupling adjuster is in its standard setting Increase or d
13. mping adjustments A simple rule is that increased spring preload should be followed by an increase of rebound damping by 2 steps 1 2 turn When you feel that you have achieved an improvement go back to where you started and check once more Be observant of other relevant factors such as snow conditions temperature etc Test run to make sure whether further fine adjustments should be made Reduce Compression damping if the suspension feels Harsh Hard 16 Preventive maintenance and regular inspection reduces the risk of functional disturbance If there is any need for additional service please contact an authorized Ohlins Service Centre Cleaning Clean the shock absorber externally with a soft detergent Use compressed air Be careful that all dirt is removed Lift the bump rubber and clean the area below Keep the shock absorber clean and spray it with oil WD40 CRC 5 56 or equivalent after washing Wipe off excessive oil with a cloth Mm Caution Never spray water directly into the adjuster knobs and or the ball joints Inspection 1 Check ball joints for possible excessive play or stiction 2 Check the piston shaft for leakage and damage 3 Check the ice scraper for excessive wear 4 Check the shock absorber body for external damage 5 Check the external reservoir for damage that can restrict the floating piston from moving freely 6 Check for excessive wear of rubber components 7 Ch
14. orber body Patented ice scraper US Pat no 5584 368 External Reservoir with Hose Connection External Piggyback Reservoir Fluid is forced through needle valves at a low rate of flow Fig 6 and through a number of orifices in the piston Fig 7 at a high rate of flow The flow through these orifices is regulated by shims thin steel washers that at high pressure are deflected to open for the fluid On most models the needle valve can be adjusted from the outside By altering the size of the shim stack Fig 8 i e number thickness diameter the characteristics of the damping action can be changed This should only be done by an authorized Ohlins service workshop Compression damping When movement of the snowmobile causes compression of the shock absorber the fluid flows through the needle valve combined compression and rebound valve in the piston rod If the velocity of the compression movement is high i e in the case of rapid compression this will not be sufficient and consequently the shims underneath the piston will open to allow for a greater rate of flow The fluid that is displaced by the volume of the piston rod is forced into the external reservoir via a separate compression valve The separating piston is displaced thus increasing the gas pressure Rebound damping When the spring forces the shock absorber to extend again the fluid flows back through the needle v
15. rs e The snowmobile is wagging its tail when letting off the throttle coming in to corners for example fig 18 A possible cause the centre shock absorber takes too much of the vehicle weight which is the same as the front and the rear shock absorbers taking too little of the vehicle weight Since the rear ride height is already decided by the rear spring preload only the front and centre shock absorber springs preload remain to adjust Try either of these changes Increase the preload on the front shock absorbers in 3 mm or s steps or decrease the preload on the centre shock absorber in 2 mm or 1 12 steps As a rule of thumb the front ride height with rider should normally be 4 s of the total travel fig 19 Limiter straps lf your vehicle has limiter straps or similar adjuster for the centre shock absorber we advise to read your vehicle service manual for proper setting The limiter strap must limit the suspension travel before the shock absorber is fully Note extended The limiter straps protect the centre shock absorber from being torn apart Very high tearing forces can occur for instance if you jump with the snowmobile and land on the rear part of the rear suspension Therefore the limiter straps must always be shorter than the shock in fullly extended position Figure 20 Total suspension al travel T 3 4 2 3 ofthe suspension travel
16. xternal reservoir connected by a hose Fig 4 or fixed directly on top of the shock absorber Fig 3 In some models everything is fitted inside the main shock absorber Fig 2 A few shock absorbers are of emulsion type oil and gas mixed inside the shock absorber Fig 1 Pressurisation of the fluid is made with nitrogen The pressurisation prevents cavitation of the fluid and the shock absorbing action is therefore more even The external reservoir also contributes to better cooling of the fluid giving longer service life for the fluid as well as the components All Ohlins shock absorbers for snowmobile also have a patented bronze ice scraper Fig 5 on the piston shaft preventing ice from damaging the seals and moisture from entering the shock absorber Separating je Piston I Internal Gas Reservoir Emulsion Shock Absorber hlins shock absorbers with external rebound adjustment have an 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 and rebound damping hlins shock absorbers provide the possibility of adjustment making them adaptable to most vehicles riders and ranges of use All of the shock absorbers with springs have adjustable preload of the spring action Shock abs
17. 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 Go explore Ohlins Racing AB All rights reserved Any reprinting or unauthorized use without the written permission of Ohlins Racing AB is prohibited Printed in Sweden Note The shock absorber is a very important part of the vehicle and will affect the stability Read and make sure that you understand the information in this manual and the mounting instructions before you use this product If you have any questions regarding installation or maintenance please contact an Ohlins dealer Ohlins Racing AB can not be held responsible for any damage to the shock absorber vehicle other property or injury to persons if the instructions for installing and maintenance are not followed exactly A Warning This product was developed and designed exclusively for a specific vehicle model and shall only be installed on the intended vehicle model in its original condition as delivered from the vehicle manufacturer This product contains pressurized nitrogen gas N Do not open service or modify this product without proper education authorized Ohlins dealer distributor and proper tools A After installing this product take a test ride at low speed to make sure that your vehicle has maintained its stability If the suspension makes an a
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