This input shaft is designed for Baotian BT49QT-791112 scooter engines.
This shaft is designed for 50cc 4-stroke engines type GY6 model 139QMA.
Total length: 154,5mm
Right-hand thread M10x1.25 over a length of 11mm.
Threaded side, fluted part 22 teeth, head diameter 12mm over a length of 21.5mm.
Trunnion length 12.5mm with a diameter of 17mm ground opposite the thread.