Replacement oil pump gear for use on Chinese 4-stroke GY6 50ccm 139QMB/QMA scooter engines. There are 2 crankshaft versions being factory installed in GY6 scooter engines. They differ only in the drive gear for the oil pump on the right side. The old version ships in almost all GY6 scooters and has a gear with 16 teeth. The new version has 22 teeth.

Attention: Please count the number of teeth on the gear for the oil pump so you know whether you need the oil pump with 16 teeth or 22 teeth.