Cylinder Kit 150cc 57.4mm for China 4-stroke GY6 125 152QMI, 150 157QMJ150cc Cylinder kit for all 125/150cc 4 stroke Chinese scooters which use the GY6 157QMI or 152QMI enginesCan be used as a direct replacement for 150cc engines as standard or a performance upgrade to 125cc enginesIf fitting to a 125cc scooter then necessary up jetting will be required (approx 10%)Kit is supplied with required top end gaskets, barrel, piston, rings, pin and clipsIf purchasing this kit for the Sym 125cc scooters, please ensure your engine is the GY6 version (cylinder head stud holes have a distance of 63mm hole to hole, outside to outside measurement)