GOOFIT Performance Big Bore Cylinder Kit GY6 80cc 47mm for 139QMB ATV Scooter Moped Go Kart Inner Diameter of Cylinder: 47mm,Outer Diameter of Piston Pin: 13mm Include Cylinder,Piston,Piston Ring,Piston Pin,Piston Pin Clip,Valve Oil Seal,Gaskets,Tensioner Gasket,Exhaust Gasket,Intake&Exhaust Studs,Exhaust Nut One week money back guarantee if not satisfied Easy installation with video instruction,you can visit the video on our Facebook homepage and Youtube. High Performance Upgrade 47mm Cylinder Rebuild Kit for GY6 49cc 50cc 60cc 80cc engine