2008 Arctic Cat 366 ATV Service Manual, Page 43Get this manual
PISTON ASSEMBLY NOTE: Whenever piston, rings, or pin are out of tolerance, they must be replaced
Measuring Piston-Ring End Gap (Installed) 1Place each piston ring in the wear portion of the cylinderUse the piston to position each ring squarely in the cylinder2Using feeler gauge, measure each piston-ring end gapAcceptable ring end gap must be within specifications
CleaningInspecting Piston 1Using non-metallic carbon removal tool, remove any carbon buildup from the top of the piston2Inspect the piston for cracks in the piston pin, boss, top, and skirt areas3Inspect the piston for seizure marks or scuffingIf piston is scored or galled, replace it with new one4Inspect the perimeter of each piston for signs of "blowby" indicated by dark discoloration"Blowby" is caused by worn piston rings, excessive carbon in ring grooves, or an out-of-round cylinderRemoving Piston Rings 1Starting with the top ring, slide one end of the ring out of the ring-groove
Measuring Piston Pin (Outside Diameter) and Piston-Pin Bore 1Measure the piston pin outside diameter at each end and in the centerIf measurement exceeds specifications, the piston pin must be replaced