I canged a yerf dog go kart to use a different motor cant figure outwhat clutch i need?

the gokart is the yerf dog #3206/#4206 if u need to see what the go kart looks like here is the manual link http://www.yerf-dog.com/manuals.html but i change the rear axel i cut it off the frame and where the pasenger tire was is now on the driver side and dirver side vice versa the sprocket on it is still the original from factory the sprocket has 31 teeth the motor im puting on it is an 11 hp the shaft is1 in. in diameter x 2-7/8 long 3/8-24 UNF 1/4 Keyway is the spec on the shaft now once i put the motor on im completely stumped as of to what centrifugal clutch i need for it can anyone plz help ....ty ty