I would toss the hoot gearbox in the garbage and keep the rest. If you payed 250 for all of it that's not a bad deal the motor with all the other parts seperately are worth more than that. Go to bicycle-engines.com and get a grubee skyhawk stage 3 complete gearbox for 119 and you will be good to go. Or wait till the grubee's 4g belt drive becomes available soon on the same web site and you won't hear a thing but the motor.. It's a new belt drive system that's quiet as a mouse. There are some other american made gearbox's out there but you'll have to spend a lot more. If that's cool ez motorbikes I hear has a sweet setup soon to hit the market. also one from firebelly looks like a great option Check out some of the other threads that feature more info under the 4-stroke catagory. Even the grubee skyhawk stage 3 makes some noise I'm sure it's not as bad as the one that came with your kit.