What are the 3 positions of a petcock on a 94 Suzuki GSXR 750 and which way does each point?

Almost every motorcycle petcock has a main or "ON", reserve or "RES" and off or "OFF" position marked on it. If the markings are not there, check your fuel lines. The main line will begin on a higher point on the gas tank than the reserve. The off position is halfway between the main and reserve positions.