Stock accelerator pump covers permit only a 60% - 70% fuel charge in the pump chamber. Turn the throttle and air in the chamber is compressed and fuel is delayed. The result: Hesitation or Bog. The Wirtz QuickShot cover completely fills the pump chamber with fuel, and provides instant fuel delivery, eliminating the hesitation and bog. *Fits all 4-Stroke Keihin FCR carburetors *Instant response to throttle movements *Improved low end performance *Reduced hot engine stalling *No modification required - simple bolt-on