uncle Bob is right, if you know how the machine that you are using works, you will be able to better understand how to use it and make it do the work not you. layinlo usmc, you forgot to mention that if he's going to add 4 teeth that that would need to be done on the rear to increase the lowend touque. Personally I think I would drop 2 teeth off the front sprocket, makes a great improvement without loosing sensable top speed.