Fuel reserve
（重定向自Reserve fuel tank）
In motorcycles, small aircraft, and cars, fuel reserve is the extra fuel reserved by the manufacturer in the fuel tank of a car, small aircraft, or motorcycle before the main fuel capacity runs out.
In motorcycles, when the main fuel runs out, the rider has to manually turn the reserve knob, usually located in the left part of the engine, to the reserve position. This allows the rider to use the remaining fuel.