9. CYLINDER/PISTON UXV 500 Spread each piston ring and remove it by lifting up at a point opposite the gap Do not damage the piston ring by spreading the ends too far. Clean carbon deposits from the piston ring grooves. INSPECTION Piston ring Inspect the piston rings for movement by rotating the rings. The rings should be able to move in their grooves without catching. Push the ring until the outer surface of the piston ring is nearly flush with the piston and measure the ring-to-groove clearance. Service Limits: Top: 0.08 mm (0.003 in) 2nd: 0.065 mm (0.0026 in) Insert each piston ring into the bottom of the cylinder squarely. 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: 1 mm (0.04 in) 9-4