Limitation for Kymco scooters and China Standard quality replacement crankshaft for 50/90 cc 4 stroke engines (GY6 50, 139QMB / QMA). The crankshaft is supplied fully pre-pressed with main bearings and connecting rods. In the GY6 engines 2 different versions already be installed in the factory. They differ only in the oil pump drive gear on the right side. The old version is installed in almost all scooters and has a gear with 16 teeth. The new version has 22 teeth and is used for example in new Rex models. Please count the gear teeth for the oil pump drive for safety. In the product photo the gear in question is also matched in detail.