Outer Diameter (pulley): 118mm Outer Diameter (clutch bell): 115mm Inner Diameter (clutch bell): 107mm Inner Diameter (clutch): 12mm Outer Diameter (shoes): 104mm Uses 6901-RS bearing Clutch Bell Inner Diameter (splines peak to peak): 11mm Number of Splines (clutch bell): 22 GY6 50cc Clutch Assembly for 139qmb 139qma engine. Spring Overall length 32 mmWidth 7.65 mm