Scooter Parts Catalog Pistons and Piston Rings sets for your 50cc, 110cc, 125cc, 150cc, and 250cc scooter engine. Included in the cylinder parts group are scooter pistons, intake valves, exhaust valves, rocker arms, chain tensioning parts, valve springs complete cylinders and more. Rebuild or upgrade your 4 stroke gas scooter engine with new piston & ring kit parts. If you want to upgrade your scooter's performance check out our High Performance Cylinder Kits. We ship a wide range of piston & ring kits for Chinese-built 50cc GY6 QMB139, 125cc GY6 QMI152/157 and 150cc GY6 QMJ152/157 engines.