2003 Polaris MSX 140 Personal Watercraft Service Manual, Page 68Get this manual
EngineCooling W120HO- DFI Engine Inspection 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 bottom of skirt at 90 angle to the direction of the piston pinRecord 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, determine if piston or cylinder is worn and recondition or replace as necessaryPiston to Cylinder Clearance Service Limit: .0062.00752 (.157.191mm) 10mm