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New 2007 Carb information

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James Dean (JD jetting) posted this on the "R" site. It refers to the "R" model, but according to the Honda website, both models get this new carb.

08-04-2006, 10:52 PM

James_Dean

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2007 CRF450R Carburetor Updates

The 2007 CRF450R has some major changes to the bigger, 41mm FCR carburetor. These updates mostly focus on the accelerator pump cover and linkage that works the accelerator pump.

--The new carburetor has a revised accelerator pump linkage that "pushes" the pump diaphragm with more pressure, unlike the flexible "spring" linkages of past years. The pump timing adjustment screw now turns OUTWARDS to add freeplay, opposite from past years pump timing screw.

--There is a new cam and roller arrangement that determines the pump stroke instead of a bottoming rivet on the diaphragm. Therefore, the diaphragm is new and lacks a bottoming stud.

--The pump now has a fuel inlet on the BOTTOM of the cover. The pump's inlet check valve is located IN THE COVER, and no longer in the float bowl.

What this results in is a pump that gives an immediate, stronger squirt of fuel, which finishes it's full stroke in the first half of the throttle range. The pump force is comparable to a wired or stiffly banded 2006 linkage, with a stroke limited volume.

--The carburetor now has a different needle, with only 5 clip position, and new retainer bolt in the slide. The needle is longer and cannot fall thru the slide when the clip is removed. The retainer is more like a bolt with hex head instead of an Allen screw. The larger size requires a new top cover for the carburetor also.

Pilot jet- #42

Pilot air- #100

Needle- NJYR #3

Main jet- #178

Accelerator Pump Leak Jet- #50

See pictures at-

2007 vs 2006 CRF450R CARBURETOR PICTURES

James

Linkage- 2006 (Left) - 2007 (Right)

http://www.pbase.com/image/64621998/medium.jpg

Linkage Cam Roller-

http://www.pbase.com/image/64621986/medium.jpg

Pump Covers- 2007 (Left) - 2006 (Right)

http://www.pbase.com/image/64622000/medium.jpg

http://www.pbase.com/image/64621955/medium.jpg

Pump Diaphragms- 2003-6 (long stud), 2002 (shorter stud), 2007 (flat rivet)

http://www.pbase.com/image/64621953/medium.jpg

Carburetor Needles and Retainers-

http://www.pbase.com/image/64621952/medium.jpg

__________________

'06 450XC

'05 CRF450X

'04 CRF250R

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sweet, i will look into this before i buy my '07. Gonna slang the 05' at the end of the season and get a new one

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sweet, i will look into this before i buy my '07. Gonna slang the 05' at the end of the season and get a new one

Just curious. What does it mean to slang your bike?

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Is it known if these 07 carb changes will apply to the X?

I read in Dirt Rider about possible future fuel injection on the R, I think works bike spy report. If true for production models then looks like 08 would be earliest.

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Krannie,

I have a '05 450X and had thought about putting on a Boysen Accelerator Pump. Now I'm thinking about just buying a 2007 450X carb for my '05. Would this work as a simple replacement or would there be more involved? Any idea of cost?

I'd appreciate an opinion.

Scot in Colorado

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This is weird.

I just got done trying to replace my 2007 CRF450x stock needle with the stock CRF450r needle. I was told to do this by the dealership i bought it from and my local shop to do this. The stock R needle will not work with the 07 450x carb. Also my 07 x stock needle does not have any clip positions it only has one. Can anyone tell me why this is. and does anyone make a 07 CRF 450x needle with a crf450r taper?

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This is weird.

I just got done trying to replace my 2007 CRF450x stock needle with the stock CRF450r needle. I was told to do this by the dealership i bought it from and my local shop to do this. The stock R needle will not work with the 07 450x carb. Also my 07 x stock needle does not have any clip positions it only has one. Can anyone tell me why this is. and does anyone make a 07 CRF 450x needle with a crf450r taper?

This is curious. Why it wouldn't interchange since these carbs are very close in comparison. I've read here, to use the optional needle for the '04 450R (Honda part#16233-men-671) & it will work in the '07 450X ? Is this correct?

These are good questions for JD since he has obviously had a lot of "hands-on" with these carbs

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This is curious. Why it wouldn't interchange since these carbs are very close in comparison. I've read here, to use the optional needle for the '04 450R (Honda part#16233-men-671) & it will work in the '07 450X ? Is this correct?

These are good questions for JD since he has obviously had a lot of "hands-on" with these carbs

16233-men-671 was the part # of the needle i tryed. I can confirm that it does not fit in the 07 450x carb. Well at least my carb (lol). I dont know if I need to get the R needle retainer to use the R needle but it looks like the R retainer wouldnt fit either.

If anyone could help me it would be really appreciated. I might start a thread about this too.

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This is weird.

I just got done trying to replace my 2007 CRF450x stock needle with the stock CRF450r needle. I was told to do this by the dealership i bought it from and my local shop to do this. The stock R needle will not work with the 07 450x carb. Also my 07 x stock needle does not have any clip positions it only has one. Can anyone tell me why this is. and does anyone make a 07 CRF 450x needle with a crf450r taper?

If you change the needle the JD needle will work. I used the middle possition and it works fine.

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If you change the needle the JD needle will work. I used the middle possition and it works fine.

If i put the clip on my needle it wont slide into the needle retainer? Am I doing something wrong? Also did your stock needle have multiple positions or only one. My needle only has one.

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If i put the clip on my needle it wont slide into the needle retainer? Am I doing something wrong? Also did your stock needle have multiple positions or only one. My needle only has one.

Put the clip on the needle and place it into the slide first, before the retainer. Then install the retainer with brass washer, spring, and screw - separately from the needle.

James

medium.jpg

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16233-men-671 was the part # of the needle i tryed. I can confirm that it does not fit in the 07 450x carb. Well at least my carb (lol). I dont know if I need to get the R needle retainer to use the R needle but it looks like the R retainer wouldnt fit either.

If anyone could help me it would be really appreciated. I might start a thread about this too.

If you look at the last pic posted by Krannie (above), you see the the 2 needles from the '06 & '07 450R. The '07 is somewhat different from the '06, *BUT* the '07 450R needle in the pic above is the same (newer) style as used in the '07 450X. From what I see in the pic, the '07 R needle has multiple clip postitions.

Bottom line:

'07 R uses multi postition needle.

'07 X uses a needle with only one clip postion. Both needles are styled the same with exception that the R needle is adjustable..... the X needle is not.

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If i put the clip on my needle it wont slide into the needle retainer? Am I doing something wrong? Also did your stock needle have multiple positions or only one. My needle only has one.

I havn't done this myself on mine yet, but from what I'm reading here in these posts, You are suppose to put the clip in the desired postiton on the needle & then drop the needle down into the slide. Then the retainer assembly goes on over the needle?

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I havn't done this myself on mine yet, but from what I'm reading here in these posts, You are suppose to put the clip in the desired postiton on the needle & then drop the needle down into the slide. Then the retainer assembly goes on over the needle?

That is how I did it on my 08.

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Stock 07 needle only has one postion. The JD kit will work fine, that's what I am running on my 07.

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