crf450r carb in a 400ex

[brianC400X]

I read a post earlier today here and it got me curious. I went to the honda website and found the specs for the crf450r. It list the carb as a keihn flat-slide 40mm. Is this in fact a 40mm FCR and if it is has anyone slapped one in thier 400. What did they use for a cable? Also rumor has it they are cheaper than the 450-500 dollar 39mm fcr kits for 400ex's. Any confirmation here?

[H_W]

The 40 mm carb on the crf450 dirt bike is an FCR. I don't know anyone that has one on a 400ex. I think it would work as long as you get a throttle cable that will hook up to the carb and the thumb throttle. I have the 39 mm FCR on my 400ex, and I love it. I have since realized that the carb from the crf450 is cheaper than the 39 mm FCR, wish I had known that before I bought it.

[86atc250r]

I looked into this quite a while back. The CRF is indeed an FCR, it is a newer, more off-road friendly version - so it's a much better carb than the FCR39 the rest of us use.

The problem is that with it's somewhat different outside dimensions, I've been told that it doesn't fit very well in the 400EX.

[Racer over 40]

I have one on my 440EX stroker. It is one off the '03 CRF450. I have done nothing but richen up the fuel screw . The jetting has been spot since installation. I also use the CRF450 twist throttle and cables. It looks factory installed. The cable I was told to install was the TRX 300 utility version if I wanted to use the thumb throttle. The bell side of the carb will require a small section of 2 1/4" radiator hose,2 1/4" exhaust(2-3") to adapt the carburetor to the 400EX air cleaner boot. I highly recommend this carb to anyone considering a FCR for their 400EX

[Waynes400ex]

Race Over what all is done to your motor? How does it run ?

[VegasEx'r]

Racer Over 40, do you have any pics of the carb installed?

[ScreaminZ400]

is there any other parts that can go onto an ex from a crf?

[Waynes400ex]

I have heard the cam chain but someone else said it didnt fit?

[Ryan]

Originally posted by Waynes400ex
I have heard the cam chain but someone else said it didnt fit?

The CRF450 cam chain does fit. There was a big thread about it somewhere.

[Racer over 40]

Sorry that I have not responded sooner, But I just got back from the Kawasaki / Vegas dealer show. I can tell you now that there is NO answer from Kawasaki for the new Honda/Yamaha performance quads. My 400EX motor mods consist of a 4mm stroker crank, JE 11:1 / 88mm piston, ported/ flowed big valve head, HRC cam, Sparks 8 plate clutch kit, Sparks X-6 exhaust, Four Stroke Tech oil cooler kit, lightened flywheel and the CRF450 FCR 40mm carb. It runs VERY well on a 50/50 mix of VP C12 / 93 octane pump gas.. As for photos of my CRF carb install, those that are interested just PM me and give your e-mail address and I will try to respond promptly. I have not taken any photos as of yet but would do so if there is interest. Thanks.....