The Drivetrain (axle, sprocket, disc brake, wheels, and bearings)
The drivetrain is the most important part of the go kart, Its how you move and stop! According to your frame design you need an axle with a key way. A keyway (and key) is used to lock a component to a rotating shaft so the component will spin with the shaft, and not slip (toystory_4WD). Look at some parts and this will make more sense to you. You will now need to worry about your transmission. There are two main types, a clutch ($30), or a torque converter ($200). A centrifugal clutch is the most common because it is the cheapest and is simple to use. A clutch works like this: There are two parts to a clutch, an inside and outside drum. the inside drum is connected right to the PTO shaft (thing that sticks out of an engine ) and is loaded with springs. The outside drum is installed the same way but can rotate without the PTO shaft rotating. Now you might be thinking why do i need one? Without one, as soon as you start your engine (will be really hard to start because shaft cannot rotate) Your go kart will go without you pushing the gas. What a clutch does is it lets you have the engine running, without the kart moving. When you start your engine (on lowest throttle) the inside drum will rotate without the outside drum rotating. The out side drum has the sprocket for the chain on it, and the chain connects to the drive sprocket on you axle. When you give the engine throttle (pushing on the gas pedal) The inside drum expands and grips the outside drum and makes the chain move. When the RPM of the engine is increased the inside drum expands get it? It is kind of hard to explain how a clutch works without showing you what it looks like but just look it up on youtube, there are a lot of videos about it. A Torque Converter (TC) changes the gear ratio at all times so you get a lot more speed and acceleration and they are definately worth the money, but they are a little harder to understand and more complex to settup. Once again there are more detailed links for TC's and Clutches on other threads, but im just going over the basics. There is a cheaper option such as a 1 wheel drive kart. That means that instead of having an axle you bolt the sprocket to the wheel and bolt it to the side, so only that wheel moves. It is not as efficient but will save you money!
diagram of rear live axle:
http://www.willardssmallengines.com/...large/3987.jpg
So how does the one wheel drive work is this picture supposed to show it? I thought the sprocket was supposed to be connected to the wheel...
