49cc Crankshaft 16T for GY6-50 QMB139 49-80cc Scooter Motors. Click Here for specs and fitment:

This 49cc scooter crankshaft is the most popular one used by the off brand 50cc scooter manufacturers.
Overall Length: 247mm                                                                                                                Oil pump drive sprocket =16 teeth                                                                                          Thread Size (tapered side): M10x11.5mm
Thread Size (spline side): M12x15mm
Bearing Outer Diameter (tapered side): 42mm
Bearing Outer Diameter (spline side): 47mm
Number of Splines: 26
Thin Gear=17th Thick Gear=16th
Tomos Nitro 50 # 13000-BE2-A003 This scooter Crankshaft fits most QMB139 (GY6-50), 49cc models.
E-Ton (Eton)# 811586 Not exact but Workable Part
E-Ton (Eton)# 813466 Direct Fit
Tomos Nitro 50 # 12191-BE2-A000