7. CYLINDER HEAD (2-STROKE)/ CYLINDER/PISTON VITALITY 50 PISTON RING INSTALLATION Install the piston rings onto the piston. Apply engine oil to each piston ring. · Be careful not to damage or break the piston and piston rings. · All rings should be installed with the markings facing up. Top · After installing the rings, they should rotate freely without sticking. Second Side Rail Oil Ring Side Rail Measure the connecting rod small end I.D. Service Limit: 13.06mm replace if over Measure the connecting rod to piston pin clearance. Service Limit: 0.06mm replace if over 7-17