What It Is
The Quickshot 2 is the second-generation accelerator pump cover from the geniuses at Boyesen Engineering. Designed specifically for the '07 Honda CRF250R and CRF450R, the QS2 can also be fitted on all other four-stroke MX bikes with some slight carburetor modifications.
When the original Quickshot was introduced, we raved about its ability to eliminate the bog that four strokes suffer from when the throttle is twisted open quickly from idle. For 2007, Honda relocated the float bowl check valve to the accelerator pump cover, and the QS2 takes that design one step further. Bolting the QS2 on takes only a few minutes and can be done at the track if some precautions are taken to clean the carburetor and surrounding area first. (For our sea-level locale, the following are the carburetor settings we tested the QS2 with: 168 main jet, NKUS needle (2nd clip from top), 48 pilot jet, 45 leak jet, fuel screw 1 3/4 turns out, accelerator pump timing .115".) The difference we felt in throttle response with the QS2 bolted on was astounding. In stock condition, it was possible to kill the CRF250R's engine by holding the throttle wide open from idle, but with the QS2 installed, instant throttle response was gained. On the track, the bike felt livelier and much snappier, with no hesitation at all. Thanks to the instant throttle response, our test bike felt faster and more powerful, too.
The QS2 is model specific, but it can be used on other bikes if the ball bearing in the float bowl's check valve is tapped out with a small punch, first.
Once again, the guys at Boyesen have hit a homerun. The Quickshot 2 is, dollar for dollar, one of the best investments you can make if you ride a Honda CRF.