Ok Hough I appreciate your input, the output shaft off of the gear box turns at 1/3 the speed of the engine ok. In my mind I know the purpose of the gear box and thats what it does. The purpose of the other 3 sprockets is to change that 3/1 ratio correct? (plus theres the sprocket on the wheel) How does this bike change ratios without changing a sprocket to a different size? I now know why he didnt put the drive chain to the rear wheel directly to the output shaft coming from the gearbox. What is the final ratio between the engine rpm and the rear wheel sprocket with this setup? How does this bike change from a 70 to a 60 then a 48 tooth gear ratio? Im starting to feel stupid.