This 6 Pole Magneto Cylinder applies to (and is not limited to) 50cc 70cc 90cc 110cc and 125cc electric start automatic engines. Most commonly used for 125cc electric start ATV's, dirt bikes and buggies/go-karts.     Inner Diameter (ID): 86.7mm    Outer Diameter (OD): 109.7mm    Overall Height: 47.1mm    Center Hole Mount (Tapered): 15/18mm