2008 Polaris ATV Predator 50, Sportsman Outlaw 90 Service Manual, Page 66Get this manual
ENGINETRANSMISSION Piston Inspection
NOTE: refer to specifications at the beginning of this chapter as required1Measure piston outside diameter at point 3mm up from bottom of piston at right angle to direction of piston pin5Measure connecting rod small end IDReplace crankshaft if connecting rod small end is out-of-round
6Piston Piston Pin
Measure piston ring to groove clearance by placing the ring in the ring land and measuring with thickness gaugeReplace piston and rings if ring-to-groove clearance exceeds service limitPiston Ring