Minibike Go Kart Clutch 3/4″ Bore 10 Tooth for #40/41/420 Chain 428 Chian There are 19mm and 20mm bore,Please Check the Outside diameter you need before order 420 Clutch Outside diameter: 10 Tooth 19mm (3/4″) or 20mm bore ,Fit #40/41/420 chain Total width: 3″ Clutch back to sprocket: 2 1/2″ 420 clutch 19mm 3/4” Bore Fits 2-6.5hp Honda Honda Cloned Engines GC160, GC190, GX120, GX140, GX160, GX200 Perfect For Go Kart Minibike Baja Mini Bike MB165 MB200 (Baja Heat, Mini Baja, Baja Warrior) Common clutch for 3.5-7hp engines using #40/41/420 chain Briggs Stratton and 2 – 6.5 HP With 3/4″ Shaft Tecumseh Engines 2 – 6.5 HP With 3/4″ Shaft 428 Clutch : 13 Tooth 19mm (3/4″) or 20mm bore Fits a 428 chain. 19mm metric bore. HD 428chain clutch for Honda import Gokart and Buggy engines with parallel 19mm engine drive shafts. Fits the wide range of Honda import clone engines used in Gokarts and Buggies normally on 3.5-7HP 170F engine styles.