New in the Package Centrifugal Clutch, 2 set screws and 3/16″ x 3/16″ x 1/2″ key for minibike chopper, barstool racer, mini bike or go cart.3/4 inch Bore Clutch has 10 teeth for use with #40 and #41 chain. (Tooth tip to tooth tip measurement is 1/2 inch).Clutch will work on 2HP to 8HP engines with a 3/4″ diameter crankshaft ( Briggs & Stratton Tecumseh Honda Kohler ).Can be mounted with the sprocket facing towards the engine or can be mounted facing away from the engine.