The AFP is a vacuum-operated diaphragm that is activated by the rear cylinder vacuum of the Honda Shadow VT600 ('99-'07). The one shown here was actually recalled. The easiest way to get rid of it is to run a line from the gas tank to the carburetor (always put a fuel filter in that line), then pull the hose from the port and use a specially-made AFP plug to close the port. DO NOT FORGET TO PLUG THE PORT. As always, we want to help make your life easier, so WE SELL THESE!