Designed for inline four-cylinder performance to offer higher horsepower gains with the world's top motorcycle road race and drag race teamsOffer smooth, controllable throttle response with precise fuel-metering demands with high-volume fuel/air required by race enginesFlat throttle valve design provides the strongest signal for precise and instantaneous throttle responseAccelerator pump spray nozzle shoots fuel directly into the intake tract for immediate engine responseCheck carb spacing to verify fitments use spacing chart on how to check spacingFloat bowl vent allows atmospheric pressure into float bowl for fuel flowInclude adjustable accelerator pump and adjustable idle screwAdjustable throttle return spring allows spring return pressureIncludes enrichment starter system for easier cold startingJet needle has easy adjustment slots for quick tuningUse Genuine Mikuni jets and parts for best resultsMade in JapanJetting may need to be changed per application, see chart for included jetting.Larger-diameter spigot O.D.'s may require different mounting flanges.