How does a motorcycle fuel injector work? The fuel is sent through the injector at high pressure to atomize it into droplets just a few microns in diameter to increase the fuel's surface area, and it is then sprayed into the intake passage through the tiny holes—usually 4 to 12—at the tip. A fuel injection system consists of fuel injectors and a fuel pump. As soon as one twists the throttle of a bike, it activates the pump. The pump then transfers fuel to the injectors. Then, the injectors inject the fuel into the combustion chamber.