2005 Ski-Doo Racing Handbook, Page 49Get this manual
SECTION 03CHASSIS PREPARATION
As you can see, low speed dampening remains the same until the shim stack bottoms out against the valve stopperThen the dampening becomes significantly stifferThis is sometimes referred to as progressive dampeningAnother similar way to achieve this type of dampening is to use multiple stacks of large and small shims Under dampening may be due to an aerated shock due to low gas pressure andor old, used oilChange the oil and recharge the gas pressure to 300 PSI before altering the shock valving If the vehicle bounces or pogos lot, the problem may be too little compression dampening NOT too little rebound dampeningDo not use too much rebound dampening! Excessive rebound dampening is common errorOverdampening will not allow the suspension to recycle to full extension after an obstacle compresses the suspensionThis situation (called packing) will eventually bottom the suspension and not allow it to cycle properly For faster weight transfer under acceleration and deceleration, use piston with more bleed slitsShock Oil and Nitrogen