2008 Arctic Cat 400/500/650/700 ATV Service Manual, Page 117Get this manual
Measuring Piston Pin (Outside Diameter) and Piston-Pin Bore 1Measure the piston pin outside diameter at each end and in the centerIf measurement is not within specifications, the piston pin must be replaced 2Measure the corresponding piston diameter at point 15 mm (0.6 in above the piston skirt at right angle to the piston-pin boreSubtract this measurement from the measurement in step 1The difference (clearance) must be within specificationsInstalling Piston Rings 1Install ring expander (4) in the bottom groove of the piston; then install the thin oil rings (3) over the expander making sure the expander ends do not overlapStagger the end gaps of the upper and lower thin oil rings according to the illustrationNOTE: Note the direction of the exhaust side of the piston (5) for correct ring end gap orientation