2000 Polaris Indy 500 / 600 snowmobile service manual, Page 173Get this manual
CLUTCHES Operation
9000 8000 7000 RPM 6000 5000 ENGAGEMENT 4000 3000 ENGINE OPERATING RANGE 250 RPM
If the weights are too heavy, or spring rate too low, the engine RPM will be low and the drive clutch will upshift too fast, keeping the engine out of its power band