Keihin 016.167 PWK 38mm Air Striker Carburetor The Keihin PWK Air Striker two stroke carburetor is refined to perfection and has set the standard among motocross racing carburetors PWK Air Striker directs air to main nozzle for improved signal and throttle response Chromed semi-flat (D) throttle valve for excellent response and more flow at high rpm Available in two popular sizes to cover all your horsepower requirements.Quad Vents: Eliminates post jump bogging from fuel plugged vent passages Throttle bores sized to give maximum power and easy jetting with jetting parts available