2000 Polaris Indy 500 / 600 snowmobile service manual, Page 113Get this manual
ENGINES General Inspection Procedures Piston InspectionMeasurement
1Check piston for scoring or cracks in piston crown or pin areaExcessive carbon buildup below the ring lands is an indication of piston, ring or cylinder wear2Measure piston outside diameter at point 10 mm (38up from the bottom of the skirt at 90 angle to the direction of the piston pin (domestic engines)For Fuji engines, measure 12 (12.7mm) up from the bottom of the piston skirtRecord the measurement for each pistonNOTE: The piston must be measured at this point to provide accurate piston-to-cylinder clearance measurement3Subtract this measurement from the minimum cylinder measurement recorded previouslyIf clearance exceeds the service limit, the cylinder should be re-bored (replaced if NiCaSil) and new pistons and rings installed