GY6 150 cc engine is often used to assemble the scooter.Set up for Rear Drum Brake.Set Up for Pair Emissions System.Check oil level after letting the engine idle for a few minutes, add additional oil if needed.Please measure the physical size of your engine and compare to our specifications before ordering.The difference is in the length of the rear swing arm.Different lengths have been made to accommodate different wheel sizes.For rear drum brakes only.