69mm bolt hole spacing 10 splines 7.25 mm shaft diameter 2-pin connector 12 volt electric starter motor for 50cc QMB139 4-stroke scooter engines Compatible with many brands of scooters, including models from Baja Motorsports, KYMCO, Tank, TNG, etc. 30 Day Warranty Description 12 volt electric starter motor for 50cc QMB139 4-stroke scooter engines. Compatible with many brands of scooters, including models from Baja Motorsports, KYMCO, Tank, TNG, etc.