fdj minibike go kart clutch 3/4" bore 10 tooth for #40/41/420 chain fdj fits engine 2 - 6.5hp with 3/4" shaft and 3/16" key way fits : 2 - 6.5hp engines honda gc160, gc190, gx120, gx140, gx160, gx200 fits : briggs & stratton and 2 - 6.5 hp with 3/4" shaft fits : tecumseh engines 2 - 6.5 hp with 3/4" shaft mounts onto crankshaft using bolt and washer on the end of the crankshaft. set screws not included note: centrifugal clutches are designed to be used with tires no larger than 15" tall. with a live axle kart you need to run at least a 60t sprocket and then it is only good on flat surfaces. for off road and hill climbing you need a torque converter set up.