Scooter Parts Catalog has the crankcase parts for your 50cc, 110cc, 125cc, 150cc, and 250cc scooter engine. Included in the crankcase parts group are transmission, CVT, valve, crankcase covers. starter gears, starter shafts and more. While most crankcase parts are pretty durable, all things eventually wear out or break. When that happens, and it will, we will be here to find the correct replacement part for your scooter. We stock a wide range of crankcase parts for Chinese-built 50cc GY6 QMB139, 125cc GY6 QMI152/157 and 150cc GY6 QMJ152/157 engines