accelerator pump ????

[ZeroTheHero]

How does a Boyseen quick shot accelerator pump work and what does it do?
I heard of them but never knew what they were

[bradley300]

from what i have gatherd, they cure the stutter off idle that the FCR crbs have, but really that means they are useless. if you have the carb and a/p tuned properly, you wont need the quickshot

[465Rider]

The holes are higher in the bowl, allowing more gas in. Accelerator pumps are only usefull off idle, once R's are over 2500, the pump doesn't help performance much. They may be good for Mx racing where you have to slow down for hair pin corners, then nail the throttle. I'm not sure how much good this mod does, some people say it does allot of good.

[wilkin250r]

I don't have an FCR carb, but I've heard of the problem.

Apparently, an air bubble gets trapped in the accelerator pump. As you know, liquid does not compress, but air does. Ordinarily, when the pump diaphram is compressed, it forces fuel out immediately because the liquid doesn't compress. But now with that air bubble in there, the air compresses first, and THEN shoots the fuel out, basically causing a delay in the fuel delivery from the acc. pump.

Well, duh. That's the whole point of the pump, so we get an immediate shot of fuel. It still helps, but it's not nearly as effective if it's delayed.

When you stab the throttle off idle, your jetting gets really lean for a few seconds. It's not dangerous, because you aren't going to overheat in a few seconds, but your mixture is so lean that you don't have any power. It will stumble and stutter. That's why you have an accelerator pump, to provide a quick shot of fuel right away to avoid that lean condition and give you power right away. But the whole point of having an accelerator pump is to get fuel RIGHT AWAY.

The Boyesen cover is designed to eliminate that air bubble. Without that bubble, there is no delay in the fuel delivery, thus eliminating the stutter.

That's the theory as I understand it. I bet there are a few people on here that have actually tried it.

[ZeroTheHero]

Thanks a lot everyone for the help
From what I am understanding from here is I don't really need the accelerator pump

[bradley300]

you need the accelerator pump since the carb is designed to have it. what you dont need is the quickshot. just adjust the a/p and the leak jet and it will not stumble