2008 Polaris ATV Predator 50, Sportsman Outlaw 90 Service Manual, Page 69Get this manual
ENGINETRANSMISSION Crankcase Disassembly
NOTE: Engine must be removed crankcase or crankshaft serviceto perform
CrankshaftCam ChainSprocket Inspection
1Inspect the crankshaft main bearings and cam chain sprocket for wear or damage