2008 Polaris ATV Sportsman 300 400 H.O. Service Manual, Page 134Get this manual
CVTTRANSMISSION Drive Belt Inspection
1Inspect belt for hour glassing (extreme circular wear in at least one spot and on both sides of the belt)Hour glassing occurs when the drive train does not move and the drive clutch engages the beltInspect belt for loose cords, missing cogs, cracks, abrasions, thin spots, or excessive wearBelts with thin spots, burn marks, etc should be replaced to eliminate noise, vibration, or erratic CVT operationMeasure belt width and compare to specificationReplace if any area is worn below the minimum width, if belt is unevenly worn (hour glassed) or if damaged
Drive Clutch Service