I just picled up a used 500QM in need of some work. The engine starts and runs fora bit an then quits. I took the carburetor and fuel tank apart and cleaned completely. I found the airbox fuel of fuel. I assume this is due to a bad selector valve. The top speed on this quad right now is 15 mph. It has a noise in the clutch when I bought it. I inspected and found the back disk on the drive clutch to have the splines completely gone. I purchased a good used clutch and only install the back plate that was bad. It still will only go 15 mph. How much tension should the belt have? The belt does not look to be cracked. I can rev i up in neutral an watch the driven and driven clutch move in and out and the belt raise up in the grooves of the clutches. It seems like it should react faster than it does, but I a new to the zuki setup. I drained the oil and found it fuel of fuel. I need to change the oil and need to know the weight and type of oil to be used. If anyone has a service manual I will pay to get a copy of it. What are the valve clearances as well. Any help i appreciated.