We will respond within 24 hours. With its 61mm big bore and 69mm valves, this kit is designed to fit GY6 180cc 4-stroke engines, providing improved performance and power ★ Material - Made of aluminum alloy, it boasts light weight, excellent heat dissipation, and high strength and stiffness to withstand cylinder pressure and loads. Grizzly 660 102mm 2 Big Bore Cylinder Wiseco Piston Cometic Top End Rebuild Kit 1755079970 Engine Rebuild Kit Minho GY6 61mm/2.40" Cylinder Top End Rebuild Kit With Aluminum Alloy Cylinder Kit Should you have any questions regarding our products, please feel free to contact us before making your purchase. gy6 rebuild kit ; Engine Rebuild Kit Cylinder Head Piston Gasket Scooter GY6 125 150cc 157QMJ · $64.95 ★ Minho - We make customer satisfaction our top priority. Outer Diameter of Piston Pin: 15mm