Two length styles Long case or short case Black finish Do you need a replacement a 150cc GY6 scooter & go-kart engine crankcase cover The 150cc GY6 engine is a very common scooter and go-kart engine, and are made in two case styles, the long case and the short case versions Description Do you need a replacement a 150cc GY6 scooter & go-kart engine crankcase cover The 150cc GY6 engine is a very common scooter and go-kart engine, and are made in two case styles, the long case and the short case versions. Both sport a nice black finish. The short case engine is designed for use with 10″ or 11″ diameter rear rims. The long case engine is for scooters and go-karts that use of 12″ or 13″ rear rims. Please use your rear rims to determine which case style (long or short) that you need.