1986-1991 Kawasaki 650 X-2 Service Manual, Page 59Get this manual
ENGINE TOP END 5-9 PistonCylinder Clearance
The piston-to-cyl.inder clearance must be checked, and the standard value maintained anytime piston or the cylinder block are replaced with new parts, or whenever the cylinder is rebored and oversize pistons installedeThe most accurate way to find the piston clearance is by making separate piston and cylinder diameter measurements and then computing the difference between the two valueseMeasure the piston diameter as just described, and The subtract this value from the measurementdifference is the piston clearance
Piston Ring End Gap
ePlace the piston ring inside the cylinder, using the piston to locate the ring squarely in placeSet it close to the bottom of the cylinder, where cylinder wear is loweMeasure the gap between the ends of the ring with thickness gaugeIf the gap is wider than the service limit, the ring is worn excessively and must be replaced
Piston Ring End Gap Top Second Standard 0.20O.40mm 020-0.40mm Service Limit 0.70mm O.70mm