GOOFIT 57.4mm Cylinder Head for GY6 150cc ATV Scooter 152QMI 157QMJ Engine Fit for 4 Stroke GY6 150cc Engine(read description for fitment infos) Inner Diameter of Cylinder: 57.4mm This Cylinder fits the 76mm Bolt Pattern Engine, It will not work on the 80mm Bolt Pattern Arrival within 1-2 days (Sold by GOOFIT and Fulfilled by Amazon) Arrival within 7-15 days (Ships from and sold by GOOFIT)