Yes, like we said already, check that key-way. And as for the centrifugal clutch, I got one for a previous engine and dude believe me it's not worth the trouble. The parts they sent where not sized right and if you don't have steel lathe you can forget about puting the parts on. Lucky for me I've got an assortment of dye grinders and I got it on after about 6hours of work. Then when it was on the one-way bearing it the clutch fell apart making impossible to start the engine plus I couldn't even pedal cause the added parts stuck out too far. So lucky me I was able to put the bearing back together and rode it around a little bit heres the results before the bearing fell apart a second time. Acceleration was pathetic, my top speed before at the time was 30MPH, with the centri clutch I couldn't even hit 22MPH it was horrible and the RPMS were extremely high. So I took it all the added uselessness off and Iv'e been running with the normal clutch for 2years now and couldn't be happier. So believe me from literally after putting a months worth of hours if not more into these engines I can tell the standard clutch is the best.