S&S Cycle Big Bore Super G Black Carburetor AssemblyFitment: 1955 2006 Harley Davidson big twin models 1957 2006 Sportster Models Features and Benefits: Increased venturi diameter! specially machined for 7% more flow. Exclusive black coating heat, UV, and chemical resistant Four fuel delivery ports Better throttle response O ring sealed idle mixture screw Increased air flow for more power Adjustable accelerator pump for quick throttle response and easy starting Use of the factory dual cable system