accelerator pump

[B-rad D]

do they make an better accelerator pump for a 400ex, or will a boyesen quickshot for a 450r fit a 400 (probly not)

[400exstud]

And whats wrong with the one that you already have?:confused:

[B-rad D]

a bigger pump will make the engine not bog as easy and better throttle response

[GPracer2500]

The accelerator pump is an integral component of the carb. The AP itself cannot be replaced.

The boyesen quickshot is for Keihin FCR carbs. I'm fairly certain it isn't compatable with the stock Keihin slide-valve (model QB, I think) carb on the 400EX. I'd be remiss to say I'm 100% sure on that but the Quickshot is only indicated for FCRs. The AP covers do look similar. I'd call it 99.5% sure that it wouldn't work.

You could try tuning the amount and duration of the stock AP squirt. If you're not familiar with what's involved in that and want to try, I might start by reading the info on APs found HERE (http://www.thumpertalk.com/forum/forumdisplay.php?f=104) . But be forewarned; AP tuning is generally not for beginners (or the faint of heart!).

I think the Quickshot is popular because it's a bolt-on item that lets people avoid really having to learn about the AP. Personally, I'm a skeptic concerning the Quickshot. Maybe they work wonders [shrug], but my guess is sound AP tuning can do everything for the AP that the Quickshot can do.

If you're that serious about improving the fueling on a 400EX, I might focus my efforts on replacing the carb alltogether. 04'/05' 450r stock carb, Edlebrock Quicksilver, and Keihin FCR39 are the most common choices. FCR39 is the best of them but also the most expensive. For the price of a Quickshot you're probably most of the way towards a 04'/05' 450r carb anyway (Ebay).

[bmurray]

you need to take GPracer2500 advice, he knows his stuff on carbs.