Originally Posted by Bikewithamotor
The 9 tooth is here:
Sick Bike Parts
Dont worry if it is a different size than your chain...it is just a little thinner so your chain will still fit on it just fine!
Sorry that is only for our Shift Kit or someone with a 5/8" shaft project. "This replaces the 10 tooth shift kit sprocket and is standard BMX chain width." and it will not fit on the engine.