Engineering: This 57.4mm Big Bore Cylinder Rebuild Kit is specifically designed for GY6 4-St engines, that a perfect fit and optimal performance for your 125cc, 150cc, 157QMJ, and 152QMI models. Enhanced Performance: By replacing the piston with this kit, you can significantly improve engine output and efficiency, giving your beach car, quad, buggy, or go-kart the power boost it needs for better acceleration and top speed.
