Airsal 50mm Big Bore Cylinder Kit for QMB139 50cc

Airsal 50mm Big Bore Cylinder Kit for Kymco Agility 50 and QMB139 50cc Engines. Kit includes cylinder, piston, rings, piston pin, cir clips, and gaskets. Aluminum cylinder construction for better heat dissipation. When used in conjunction with a stock crankshaft the total displacement comes out to 81.3cc! Your stock head can be reused. High compression piston included! .5mm taller than most standard 50mm big bore kits.*You may need to modify your engine case to accommodate the larger cylinder. Not compatible with Sym Symply 2. On some Chinese QMB139 engines, the cam holes may need to be enlarged.Please see our Warranty & Returns Policy. Upgrades to 81.3cc Cylinder Bore: 50mm Cylinder Sleeve Outer Diameter: 54mmCompression Height of Piston: 20mmCam Hole Diameter: 6.5mm