This jackshaft assembly is designed to transfer the power from a 49cc engine to the rear wheel of a motorized bicycle. Fits Honda GXH50 and the HS 49cc (clone) engine with keyed 5/8" shaft. Price includes complete jackshaft assembly, 10t clutch for #41 chain, #35 chain for input side, #35 master link, 10t engine sprocket, 33t input sprocket and mounting hardware. You will need a chain guard and the #41 secondary chain. We use a 56t wheel sprocket for an overall gear ratio of 18.480:1 which gives us a 31mph top speed.