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jetting and on a 2006 CRF450X when the airbox is opened up

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Well I'm trying to do some modifications for my dad's bike to improve performance. It's an 06 and still has the uncut airbox, lean jetting and stock exhaust.

I've read the following site about some mod's and was wondering, would the jetting changes there (#162 main jet, #65 leak jet, #5 clip position (stock needle im presuming), pilot screw = one and three quarter turns out) be appropriate for me?

http://www.crf450x.net/2007/02/14/ho...modifications/

The bike is an 06, with no engine modifications and im not changing the cams or the exhaust, though i'll probably remove the baffle. i'll cut the airbox though. we run preium fuel (95 octane) and live at sea-level, occasionally riding in the hills at like only 1000 ft though. temperatures range from 18-30 degrees celcious.

Should i just get the JD kit, a smaller leak jet and see if i need a bigger pilot jet?

was the jd jetting kit designed to work with an opened up airbox and stock muffler?

what on earth is a pilot screw? is that the fuel screw?

what does it mean when it says accelerator pump bleed?

also, whats the diffuser pipe in the muffler? some wierd terminology for baffle?

I'll cut the airbox and do the jetting at the same time.

should i remove the backfire screen in the airbox? (does it restrict much)

Anyway, WHAT DO I DO WITH THE JETS?

I know there's a lot of questions, but I'd really appreciate some help guys.

PS: what other mods make a difference? does the o-ring mod in the accel. pump apply to this bike?

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

what about the accel pump adjustment?

http://www.jdjetting.com/html/faq.htm#6

:thumbsup:Thanks, Mike. :thumbsup:

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Should i just get the JD kit, a smaller leak jet and see if i need a bigger pilot jet?

I've never used JD Jetting solutions however, I have called them and talked to them. They seem to be able to account for many different variables to get your jetting pretty darn close. With a little experimentation you should be able get it dialed in using their solutions. On my 07 CRF250R moving from the stock #70 leak jet to a #40 leak jet made all the difference in the world as far as a "right off idle bog"

was the jd jetting kit designed to work with an opened up airbox and stock muffler?

From reading other post I have read where Eddie has stated "Yes, JD solutions work very well with a modified air box."

what on earth is a pilot screw? is that the fuel screw?

Same thing

what does it mean when it says accelerator pump bleed?

I believe this is referring to the leak jet. Example: If you're running a #70 leak jet then you are allowing 1 oz. of fuel to be squirted into the carb and 1 oz. of fuel to "bleed" off through the leak jet back into the carburetor bowl. If you're running a #45 leak jet then you're allowing 1.5 oz of fuel to be squirted into the carburetor and .5 oz. of fuel to "bleed" off through the leak jet back into the carburetor bowl.

also, whats the diffuser pipe in the muffler? some wierd terminology for baffle?

I'm not a 100% here however, I believe the diffuser is used to cut down noise

I'll cut the airbox and do the jetting at the same time.

Yes. Do any mods you're going to do and then jet last. JD Jetting solutions should scale across all the mods you've talked about here.

should i remove the backfire screen in the airbox? (does it restrict much).

Controversial question. I have an 07 CRF250R and did remove the screen. If you do remove the screen be sure to put in a twin-air air cleaner. If you have blow back the stock filters can catch on fire, twin-air's are non-flammable.

Anyway, WHAT DO I DO WITH THE JETS?
I know there's a lot of questions, but I'd really appreciate some help guys.
PS: what other mods make a difference? does the o-ring mod in the accel. pump apply to this bike?

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

Yes, on the 06 the AP mod is still needed. From my understanding from 07 on the linkage was modified and this mod is no longer needed

what about the accel pump adjustment?

http://www.jdjetting.com/html/faq.htm#6

Check out this thread. There are excellent "step-by-step" instructions of how to set up your FCR carburetor. http://www.thumpertalk.com/forum/showthread.php?t=872855

At least this should get you started as well as get a few others posts.

I hope this help, bro.

Edited by motodogg01
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