[chief_Huba]

So I was going through the jd jetting pictures and they have pictures of a some sort of rubber band mod thing for the accelerator pump on a FCR carb.... Can any one explain this to me please?

http://www.pbase.com/jdjetting1/image/57130413

also does any one know where there is an online leak jet tuning guide? that would be most helpful :headscrat

leak jet that needs tunining http://www.r1dean.com/cart/index.php?main_page=product_info&cPath=2&products_id=4

 

[Zique7]

I'm on dial-up at the moment, so the pic is a no-go for me, but do a search for "BK mod" on here as well as Thumpertalk. Doesn't actually sound exactly the same, but maybe it'll get you started.

 

[chief_Huba]

Yeah im on TT atm and looking at the bk mod, its a little different and I dont quite understand how adding a screw where they say to add the screw is going to do anything

 

[chief_Huba]

I think that useing an ajustable leak jet does the same thing as the bk mod, change AP squirt timing, I just am sketchy about how to time it and such, I read that it should be between .5 sec and 1 sec long but how the heck do you time less than a second lol

 

[hrc nick 11]

The leak jet does just that, it leaks fuel back to the bowl from the axcel pump what goes to the bowl does not goto the engine so the larger the leak jet the less fuel goes to the engine.

The screw on the pump linkage that touches the throtal linkage, adjusts the time the squirt starts compaired to the slide movement. You want it to just miss the slide but start pretty early after movement.

The o-ring mod increases pressure and shortens duration same amount of fuel over less time.

 

[slide1in]

R&d Power Bowl Is The Way To Go!

 

[justindacey]

search "0-ring mod" on TT or ask Eddie

 

[huskyfrk]

ap mod.

go to the husky suite, video and still photo's. you don't need a fancy bowl to have it work right. don't need a boysen pump cover either. :thumbup::thumbup::bike:

 

[greenpea]

I think that useing an ajustable leak jet does the same thing as the bk mod, change AP squirt timing, I just am sketchy about how to time it and such, I read that it should be between .5 sec and 1 sec long but how the heck do you time less than a second lol

carb tuning is a steep learning curve

you have it right, the whole goal is to get your ap pump to have a squirt of about .8 seconds
the o ring/ap pump cover/leak jet are all for adjusting the squirt
keep in mind this only gives you more snap with a twist of throttle.

also remember this guys, you cant just put this items on your bike and it works fine
you need to adjust it!



i bought the new ap pump cover before i knew what i was doing
i now run a leak jet and new pump cover with no o ring

when i had just the new ap pump cover and o ring my squirt was about 4 seconds
i installed my leak jet and it was down to about 2.5 seconds
i had to take off the o ring and adjust the ap pump screw to get it to .8 seconds
this took about 20 mins taking my time

so remember this,there are many ways to get the same result
and none of this is just bolt on and go-needs to be tuned
all my bikes always had fi--now two years later i can say i fully understand a carb now

also most people dont understand the different circuits and how they overlap
heres a guide for some of you!!

 

[AgentSmith]

Here's the entire PDF on the AP mod.

Most of us have cured all bogging issues through proper jetting and the o-ring part of this mod. The second part of this mod describes shaving down the AP diaphragm rivet. Not necessary except in extreme cases.


http://www.squadpage.com/pandora/Professor RedBeard450 How-To AP Mod.pdf

 

[restukey]

http://www.youtube.com/watch?v=ool_jiy4kxQ&feature=related


Watch the black lever that rest against the set screw. It has a bit of a delay and doesn't follow the screw when there isn't an o-ring. You can use a piece of safety wire instead of an o-ring, btw. The leak jet allows excess fuel to drain back into the bowl.