M12F/46 Accelerator pump spring

The Mikuni accelerator pump spring provides the necessary return tension for the accelerator pump lever on HSR series carburetors. This spring ensures that the pump mechanism resets quickly after each throttle application, preparing it for the next movement. Consistent spring tension is vital for maintaining the correct timing and volume of the fuel shot, which directly impacts the engine's off-idle performance. Made from high-grade spring steel, it is designed to resist fatigue and maintain its rate over time. This genuine Mikuni accelerator pump spring is sold individually and is a standard replacement item during a carburetor service.