2001 Polaris Sportsman 400-500 DUSE and H.O. Service Manual, Page 127Get this manual
COUNTER BALANCER SHAFT END PLAY ADJUSTMENT
1Make sure all bearings are firmly seated in the crankcase2Measure the width of the counter balancer shaft at the bearing seats with dial caliper or micrometer, and record readingStep 2
3Measure the distance from the Mag crankcase mating surface to the balance shaft bearing using dial caliper and straight edgeSubtract the thickness of the straightedge and record