Fits GY6 125cc or 150cc Stroke Engines Works with numerous GY6 QMJ152/157 & QMI157 4-stroke engines 137mm outer bell diameter, 142mm outer pulley diameter When it comes time to tinker with your favorite GY6 powered vehicle, nothing makes the job easier than having all the parts you need at your fingertips. If this weekend’s projects call for a clutch repair, then we have you covered. This is the complete rear clutch assembly for your 125cc or 150cc GY6 QMJ152/157 and QMI157 4-stroke engine. Everything for it is here: the driver pulley, clutch bell, everything you see in the pictures. Specifications: Inner Diameter (bell): 125mm Outer Diameter (bell): 137mm Number of Splines: 19 Splines Inner Diameter (peak to peak): 13.6mm Outer Diameter (pulley): 142mm (5.6 inches)