8. CYLINDER/PISTON ATV 300/250 INSPECTION Inspect the piston, piston pin and piston rings. Remove the piston rings. Take care not to damage or break the piston rings during removal. Clean carbon deposits from the piston ring grooves. Inspect the piston wall for wear/scratches/damage. If any defects are found, replace the piston with a new one. Install the piston rings onto the piston and measure the piston ring-to-groove clearance. Service Limits: Top: 0.09 mm (0.0036 in) 2nd: 0.09 mm (0.0036 in) Remove the piston rings and insert each piston ring into the cylinder bottom. Use the piston head to push each piston ring into the cylinder. Measure the piston ring end gap. Service Limit: Top: 0.5 mm (0.02 in) 2nd: 0.65 mm (0.026 in) Oil ring: 0.9 mm (0.036 in) Measure the piston pin hole I.D. Service Limit: 17.04 mm (0.6816 in) 8-5