2003 Polaris ATV Trail Boss 330 Factory Service Manual, Page 77Get this manual
CRANKCASE INSPECTION
1Remove all traces of gasket sealer from the crankcase mating surfacesInspect the surfaces closely for nicks, burrs or damage
2Measure the distance from the MAG side crankcase mating surface to the main bearing using dial caliper and straight edge
BEARING INSTALLATION
NOTE: To ease crankshaft bearing installation, warm the crankcase until hot to the touchPlace the bearing in freezer1Install the crankshaft bearing so the numbers are visible2Drive or press the new bearing into the crankcase, using the proper driverCAUTION: Press only on outer race of bearing to prevent bearing damageG Use 70mm (2.755) driver- For crankshaft main bearings