Launched in 2002, Harley-Davidson’s VRSC or “V-Rod” family of motorcycles differs from the other four bike families (Sportster, Dyna, Softail, Touring) in several ways. This is especially true for the V-Rod gas tank. Traditionally, the gas tank was the large, teardrop-shaped container between the seat and the dashboard. In a V-Rod, however, this space is occupied by a hollow fiberglass dome. The actual gas tank is a C-shaped plastic container hidden underneath the seat, inside the chassis.
To fill the V-Rod tank with gasoline, the rider must first turn off the engine and undo a latch located behind the seat. The seat then flips forward onto the dome, exposing the gas cap. After twisting off the gas cap and refilling the tank, the rider replaces the cap, flips the seat back and secures the latch.
Getting Gas to the Engine
The gas tank and the engine are connected in a loop consisting of the fuel intake line (which pumps fuel from the tank to the engine) and the return line (which lets unused fuel from the engine flow back into the tank). This feedback system allows the fuel pump to achieve constant pressure with expending extra energy as the fuel level in the tank decreases.
A small tube called the “fuel pump inlet” extends through the wall of the tank and opens at the bottom. The other end of the tube connects to a pump that vacuums a steady stream of gasoline from the tank. This vacuum then pushes the fuel through a filter to help remove impurities. Next, the filtered fuel flows through a valve into the fuel rail – tube with several openings leading to the engine’s cylinders. The electronic fuel injectors then suck gas from the fuel rail supply and spray it into the cylinders for combustion. Even as the injectors draw gasoline away, the fuel pump ensures that fresh fuel is constantly replacing it.