ChinesePartsPro 88806 47mm 80cc Big Bore Kits 139QMB 50cc Engines 69mm Valve GY6 50CC 139QMB 139QMA scooter moped parts Cylinder Bore: 47mm / Non-EGR Cylinder / Installed 69mm Valve Cylinder Sleeve Outer Diameter: 52.7mm / Wrist Pin Diameter: 13mm / Total Piston Height: 34.4mm Compression Height (wrist pin hole to top edge of piston): 17.25mm / Cylinder head&base Gaskets Left CTV cover gasekts:15.75 Inches(short case) / 47mm Pistons sets(Piston, rings, pin, cir clips) 16*13 Roller weights/ Head Stud bolts / Oil pump& prokets(33teeth)