39mm fcr carb

[bodfper]

Is this the fcr carb that I want? fcr 39mm carb ebay (http://cgi.ebay.com/ebaymotors/Keihin-FCR-39-FCR39-Flat-Slide-Carburetor-_W0QQcmdZViewItemQQhashZitem27b386bdccQQitemZ17051 5676620QQptZMotorcyclesQ5fPartsQ5fAccessories)

[NacsMXer]

That looks like a FCR MX carb. I'm sure it can be made to work like the 450R carb, but you will need to have adapters made for the carb boots. The install is a little more involved.

If you are looking for the FCR 39 that bolts up to the 400EX with no modifications, you need to look for a Sparks or Sudco FCR 39. They are what is referred to as an "aftermarket" FCR since it is a new carb that did not come installed from the factory. They look similar to this:
http://www.spracing.ch/images/FCR39specR2.jpg

its not there. i have a fcr 450r carb. off a 06-07 quad. mine dont look like nacsmxers pic. but it is close to it though.

[NacsMXer]

His link works if you delete the < br / > from the address in the ebay link. Ebay has trouble posting on this site don't know why.

Here is a FCR MX on the left vs. an aftermarket FCR on the right. Similar, but totally different. The FCR MX is a lot larger carb.

http://www.keihin.gr/FOTO/GALERY/FCR41-FCR41MX.JPG

http://blog-imgs-27.fc2.com/m/a/r/marumasu/R0015023.jpg

http://blog-imgs-27.fc2.com/m/a/r/marumasu/R0015024.jpg

http://blog-imgs-27.fc2.com/m/a/r/marumasu/R0015025.jpg

[bodfper]

How about this carb in this ebay auction edelbrock carb 400ex (http://cgi.ebay.com/ebaymotors/HONDA-400EX-EDELBROCK-CARBURETOR-_W0QQcmdZViewItemQQhashZitem45f4151d09QQitemZ30044 7767817QQptZMotorsQ5fATVQ5fPartsQ5fAccessories)

...for this build?

-Hot rods crank stock stroke

-hd head studs

-big bore sleeve w/ JE 88.5mm piston 12:1

-take 10-11 oz off flywheel

-stg 3 hot cam

-mild port + polished head

-hd valve springs

[JOHNDOE83]

Whats so great about the fcr carb? This is a serious question...lol.

Its only a 39mm, I prefer the 450r carb, its a 42mm.

In any build for more speed or power, people always go with bigger carbs, so what is all the hype with the fcr?

The only conclusion I can come up with is that the slide is different, allowing the faster burst of power when the throttle gets hit, but thats only good for MX riding.

To me the 42mm 450r carb is best for all around power? once the rpms open up, the power is greater then that of a 39mm carb, just my opinion.

So whats all the hype about with the fcr?

And the edelbrock carbs, Ive heard bad stuff about them from alot of people, do a search on here and youll see many people having issues with them and switching to the 450 carb.

[NacsMXer]

I agree with you on the Edelbrocks... you'd be better off with the 450R or FCR carb.

I don't think the FCR is any better or worse than the 450R carb. You see guys running them like myself simply because they have been around longer than the 450R has been. Back in the day, the FCR 39 was THE carb to have if you had a modded 400EX motor. So places like Sparks racing took an aftermarket FCR (no frills like choke/hotstart) and modded it to be a direct bolt up to the 400EX. It was quite expensive back then at $350. It is even more now.

Then the 450R came along and people started putting the carbs up for sale for cheap. It was a bigger carb that offered a nice performance increase for a lot less money. That's why you see a lot more people running that carb. But at the same time, there are obviously some mods you have to do on your own to get the carb up and running on a 400EX.

Back when I bought my FCR39, the 39 was the biggest kit offered. Soon after, the FCR40 and FCR41 became available as bolt on kits. I'd be running one of those if I already didn't have a decent carb. Just not worth the $5-600 to upgrade 1 or 2 mm's bigger.

[TRXRacer1]

The FCR series carbs are hands down the best carbs ever made. Nothing of the same size compares when dialed in properly. The 42mm 450r is a good carb but it is not as efficient as an FCR. The appeal is you just can't get any better. This carb has is so good when dialed in it has slowed the progression towards fuel injection.

Will the average guy notice this great marvel over others.... maybe if they have it perfectly set, maybe not if it was back yard tuned with little knowledge. Something to remember here is that it's no accident that this is the most popular race carb by a huge margin and that not all carbs are equal. You put up a 41mm FCR against the early 42mm 450r carb and you can count on the 41mm carb delivering more then the 42mm ever will.

[JOHNDOE83]

Im gonna see what I can do to find a fcr for a good price, they seem pretty expensive, Im gonna look for a 41mm, they look like a more high performance carb, I think it will be a good upgrade.

If I can find a inexpensive one....lol.

[bodfper]

What will I pay for an fcr carb and where should I get it and what specific carb do I need? Is it necessary for me to get a new carb with the build I have in mind? Thanks for you knowledge on the carbs as well. I have considered the 450r carb but a bolt on carb would do me a huge favor.

[NacsMXer]

Originally posted by bodfper
What will I pay for an fcr carb and where should I get it and what specific carb do I need? Is it necessary for me to get a new carb with the build I have in mind? Thanks for you knowledge on the carbs as well. I have considered the 450r carb but a bolt on carb would do me a huge favor.

www.sparksracing.com for the Sparks FCR kit. Current price is $509.95.

www.sudco.com has the FCR 39 (400EX specific) for $452.55 (carb only). The FCR 41 (400EX) is $475.65. These prices are for the carbs only. Their "kit" comes with a push/pull throttle and is around $600.

As you can see, these are not cheap, which is why a lot of people go the used or 450R carb route. Hope that helps.

[odog]

i have the curtis sparks fcr 39mm they also make a bigger one for the ex.but they told me for the trails the 39mm fcr will be better. i will never go back to stock this upgrade made the single most difference on my bike.

[eotrx400ex]

buying one that would just bolt up would be nice but for the cost...hell no. i paid 150 for my fcr39 that came off a 08 yfz....i was lucky cuz its new:D came off a parts bike an never got used. but getting it to fit my ex wasn't all that hard. and i didn't spend much over 20..not including jets..most of that was for a 06+ 450r throttle cable. FYI the throttle response is ridiculous:D