Stock accelerator pump covers permit only a 60% - 70% fuel charge in the pump chamber. Turn the throttle and air trapped in the chamber is compressed disrupting fuel delivery. All the while tuning the squirt means a complicated change of the leak jet. The Result: Hesitation, bog and a tuning headache. The Patented Boyesen QuickShot 3's triple effect: 1. Completely fills the pump chamber with fuel 2. Eliminates troublesome air and 3. Provides an adjustable leak jet circuit for simple hand tuning. The Result: The ultimate in adjustable fuel injection. > Tunable leak jet maximizes volume of fuel and duration of squirt for all conditions > Investment cast and finished to precise tolerances > 25% more fuel capacity > High volume vertical check valve located in the QS3 for precise, consistent fuel metering > Stops hesitation and bog > Instant throttle response > Improved low end performance > Fits ALL Keihin FCR carbs > Simple bolt-on