spend the $$ you will be glad you did!!

I just spent about $165 at the thumpertalk store on a JD jetting kit, a Boyeson Quickshot, and a Zip-Ty fuel screw. I followed the easy to read instructions, and in about 1 1/2 hours my WR426 became NASTY! I also took off the white bros E-2 slip on muffler and replaced it with a used DSP titanium header/muffler that i bought in the thumpertalk classifieds. The throttle response is much quicker, making adjustments with the fuel screw is extra cool. Its like fine tuning in seconds! Here in Florida, the humidity makes a difference on air/fuel mixture and in seconds my bike is syncronized. The mid range power is MUCH better and the power dosnt taper off at high RPM's like before. Instead it keeps on pulling almost to the rev limiter! I do get alot more wheelspin and more un-intentional wheelies. Riding technique will help that issue i think...A very cheap way to nastify you machine! :banghead:

Wicked! I haven't got the boyesen quickshot yet, I don't think I need it.

How is that DSP exhaust? My mate has one on his 426 and it is a weapon!

It is also louder than my Procircuit Ti GP system on mine!!!

Accelerator pump cover.

It is a plate that goes on the bottom of the carby.

I have all of the above accept for the quickshot and an aftermarket muffler. Still debating if its worth it or not :banghead:

Accelerator pump cover.

It is a plate that goes on the bottom of the carby.

That's what I thought. did not know they were called "Quickshot"...Thanks Matty.

you know I never understood how a cover could improve power. How does the accelerator pump cover work does anybody know? Would a mod like that just be a plug and play operation, or will I need to make adjustments? I hate making adjustments espically to carbs. Yamaha engineers get paid good money to make it right, and I have a knack for screwing things up.

IMHO, the Quickshot gives a negligible, if any, advantage. In some cases, folks have said that it cured all their problems, including chronic halitosis. I have one, and I added it only after my bike was jetted to the point of bog-less operation. I saw no discernible improvement. But I'm just one person, so who knows :banghead:.

The theory behind it is that it has a deeper bowl and higher fuel fill channels allowing for more fuel to draw from and a quicker response for the Accelerator Pump, thereby curing the off-throttle bog common to 4-strokes. So there you go...SC

If you adjust your AP properly there is absolutely no reason to buy a quickshot cover. $80 buys a lot of beer.

Moto you said the B word now I gotta drink. Thanks for the advice fellas. I think I am probably gonna have to check out the Powernow for the same price.

Moto you said the B word now I gotta drink. Thanks for the advice fellas. I think I am probably gonna have to check out the Powernow for the same price.

There is a link floating out there somplace on how to make your own power now out of a $2 peice of sheet metal. I think I saved the document on my home computer. Send me a PM and i'll send it to you when I get home. :banghead:

What is the boyesen quickshot again?

The Quickshot accelerator pump cover claims to reduce the air trapped in the pump diaphragm cavity, which supposedly compresses as the pump is activated and lessens the fuel squirt to the motor. The theory is that the fuel passage holes in the stock pump cover are too low to completely purge the air trapped at the top. The Quickshot has 2 passages near the top, rather than down lower.

There are 3 steps to the instructions-

1)Turn the fuel screw out 1/4 turn from stock.

2)Set the pump linkage timing screw to make a gap of .100" between the screw plate and black linkage surface.

3)Install the replacement pump cover.

You can see the pump timing adjustment screw Here .

Considering the stock pump cavity has the fuel outlet on the left, you can purge the same, trapped air by simply leaning the bike to the right and twisting the throttle a few times. Under normal riding conditions, most of this air is purged from vibration and side-to-side motion.

See the float bowl chamber and leak jet that are above the pump Here .

My suggestion to most riders is to use leak jets or a diaphragm change if you want to alter the accelerator pump. It's the feature Keihin designed to make this adjustment, and what the factories use to tune.


Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now