2004 Ski-Doo Racing Handbook, Page 134Get this manual
SECTION 05DRIVE SYSTEM
POWER CURVES MILDLY TUNED VSRACE TUNED
100 90 80 70 60 50 40 30 20 10
A01D0VA
EFFECTS OF THE DRIVE PULLEY LEVER ARM, ROLLER AND ROLLER PIN WEIGHT
As you have seen in the formula defining centrifugal force, the force increases directly with the weight of the components involvedIf you want to increase the centrifugal force, therefore, the shift force, it is simple matter to increase the weight of the pressure leversIf the overall RPM is too high, heavier lever arm or roller pin could be installedThe opposite would apply if the RPM is too lowThe major factor controlling centrifugal force is engine RPMBecause the force increases with the square of this speed, you can quickly have too much force if heavy weights are used on clutch fitted to high RPM engineBecause of this relationship, you will find heavy weights used on low RPM, high torque engine types and much lighter weights used on the high RPM enginesThe effect of the weights will always be greater at high RPM, and at higher ratiosThis is true because of the relation of the force to the square of the engine speedAlso the radius from the axis of rotation to the center of mass of the counterweights increases as the roller is allowed to move down the rampsAs this radius increases, the centrifugal force increases directlyAddition of weight will affect engagement speed very little compared to the effect the weight will have at mid-range to top speedMinor changes in weight are accomplished by using various weight roller pinsThe effects of adding weight are illustrated in the following illustrationThe three curves show the engine RPM increasing from engagement speed (4000 RPM) to about 6500 RPM which is achieved at about 30 MPHFrom this point on, if calibration is accurate, there is no change in engine RPM as the vehicle speed increasesFrom the machine standing at rest to about 30 MPH, belt slippage and other factors are involved that allow the engine to get on the power