1985-1995 Polaris ATV and Light Utility Hauler Service Manual, Page 316Get this manual
ENGINES Magnum Engine DisassemblyInspection 4Inspect the balancer drive gear and pump shaft drive gear5Replace the shaft if gear teeth are abnormally worn or damaged6Inspect the balancer shaft bearingsNOTE: Due to extremely close tolerances and minimal wear, the balancer shaft ball bearings must be inspected visually and by feelLook for signs of discoloration, scoring or gallingTurn the inner race of each bearingThe bearings should turn smoothly and quietlyThe outer race of each bearing should fit tightly in the crankcaseThe inner race should be firm with minimal side to side movement and no detectable up and down movement