2004 Polaris Pro X Factory Service Manual, Page 30Get this manual
GENERAL INFORMATION 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 wear2For Libertyt engines, measure 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)
90 to pin
NOTE: 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 and new pistons and rings installed
DOMESTIC ENGINESMeasure 38 (10.0mm) up from bottom of skirt