Now-a-day everybody seem to have, or want to have a motorcycle with fuel injection, but what is an injector? An injector is basically a small electrically operated valve connected to a pressurized fuel rail. The rail is just a gallery that runs along the back of the injectors, filled with fuel under high pressure that's pumped in by the fuel pump.
When the ECU (Engine Control Unit) sends an electric charge to the injector unit, it energizes a small coil of copper wire, making an electromagnet. With this electromagnet it moves a bar inside the coil, which opens the nozzles at the end of the injector, and allowing the pressurized fuel to spray out. When the ECU turns off the voltage, a spring pushes the bar back into place, sealing off the nozzles and stopping fuel flow.
Modern fuel injection systems are designed specifically for the type of fuel being used. Some systems are designed for multiple grades of fuel and using sensors to adapt the tuning for the fuel currently used.