2003 Polaris ATV Trail Boss 330 Factory Service Manual, Page 76Get this manual
CRANKSHAFT MAIN BEARING INSPECTION
1Inspect the crankshaft main bearingsNOTE: Due to extremely close tolerances and minimal wear, the bearings must be inspected visually, and by feelLook for signs of discoloration, scoring or gallingTurn the outer race of each bearingThe bearings should turn smoothly and quietlyThe inner race of each bearing should fit tightly in the crankshaftThe outer race should be firm with minimal side to side movement and no detectable up and down movement2Replace bearings if they fail visual inspection
CONNECTING ROD BEARING INSPECTION
1Inspect bearing inserts for unusual wear, peeling, scoring, damage etcReplace as necessaryNOTE: If one insert requires replacement, replace both connecting rod bearing inserts as set
NOTE: Use the widest part of the Plastigauge to determine the oil clearance