2003 Polaris ATV Trail Boss 330 Factory Service Manual, Page 68Get this manual
PISTON REMOVAL
1Remove circlipNote that opening for circlip access is on the intake side
5Remove the top rail first followed by the bottom rail6Remove the expander
CYLINDER INSPECTION
1Remove all gasket material from the cylinder sealing surfaces2Inspect the top of the cylinder for warpage using straight edge and feeler gauge
2Remove piston circlip and push piston pin out of pistonIf necessary, heat the crown of the piston slightly with propane torchCAUTION: Do not apply heat to the piston ringsThe ring may lose radial tension3Remove top compression ring
Cylinder Warpage: .0020 (.05 mm) MAX 3Inspect cylinder for wear, scratches, or damage4Inspect cylinder for taper and out of round with telescoping gauge or dial bore gaugeMeasure in two different directions, front to back and side to side, on three different levels (12 down from top, in the middle, and 12 up from bottom)