FCR 41 or Stock carb

I have an FCR 41 carb on my old (heavily modded) XR650L and was wondering if I should swap it with the stock carb on my XR650R. My 650R carb has the 175 main and 65s pilot and the bike runs super. Is it worth the effort for the upgrade or am I just going to make work for myself for minimal performance gains? Will my bike be less reliable over the long run? The reason I am asking is because I don't know (or claim to know)as much as the Japanese engineers at Honda who built the 650R and they did not choose the FCR. If anybody is running an FCR what jets and needle position are you using? What would be the Pros and Cons?

Thanks in advance,

Max

i Don't think it would fit with even the stock tank.
Pumper carbs are very nice.
A lot of people run this carb:

http://www.xrsonly.com/parts-manufacturers-a-g-1/al-baker-xr-only/carburetor-kits/mikuni-pumper-carburetor-40mm-kit-honda-xr650r

If you want a big smile while you're riding go for the FCR...

The Mikuni is nice but difficult to jet,the FCR is by far superior. I had both.

xrmanu wrote:If you want a big smile while you're riding go for the FCR...

The Mikuni is nice but difficult to jet,the FCR is by far superior. I had both.

Yes its a cool carb , the only problem is that it does not fitt the XR650R , ( not properly ) .

Nothing difficult with some creativity and elbow grease.

xrmanu wrote:Nothing difficult with some creativity and elbow grease.

I believe you can use directly the FCR 40 MX and FCR 41 MX Racing.

Only FCR 41 "normal" it's bigger and need some mods to adapte, correct?

Well if someone knows easy way to install the FCR41 i am all ears as that is the best carb out there and i would love to run it on my bike .

Mad Frosty wrote:Well if someone knows easy way to install the FCR41 i am all ears as that is the best carb out there and i would love to run it on my bike .

Mad Frosty, from what i've "heard" there are some mods regarding FCR 41 MX installation:

http://www.thumpertalk.com/topic/579627-sudco-fcr-carb-installation-on-a-650r/

There are another FCR Keihin carb, smaller, FCR 41 MX Racing, like this one:

http://www.ebay.co.uk/itm/181105268539?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649

Is this correct info?

You are better of getting the full kit from power barn as they come with all the adapters etc you need to install the carb .
I have read that info from thumpertalk before and that was why i decided against the FCR , i want straight bolt on swap and no hassle , i am fedup with cuting , melting , grinding,.... modifying everything that i buy as it seems that nothing aftermarket fits the pig as it should and we pay good money for the parts , its all OEM for me from now on because i had enough .
rant over

xrmanu wrote:The Mikuni is nice but difficult to jet.....

Huh?
Well now Manu, you are the first to ever say this, on various forums even!
Not true at all, in fact it is easier to jet than the FCR, if only because of the fact that there is a wealth of jetting info out there.

xrmanu wrote:....the FCR is by far superior.

Also not quite true.
The FCR is a damn good carb though, but only 'better' than the TM40 if you go racing and want the last grain of performance, SM springs to mind.... and that's you innit?
For the true purpose of the Pig ie dirt riding the TM40 is more than enough, simple to jet, will effect a lower consumption with way better performance than the std carb, and is simplicity itself, the latter in contrast to the somewhat complicated FCR.


Regarding fitting under tanks it depends which FCR one has, differences are had with the slide operation mechanism. Some of them require some space made by denting the tank, others don't.
In addition, getting hold of the correct adaptors for in- & outlet is not as straightforward than for a TM40, especially valid if one buys second hand. And lastly, a FRC costs quite a bit more than the TM40, so guess what I run on mine?

The differences in performance between mikuni tm40 and keihin fcr are very small as burp said your average rider will never know the difference , where keihin shines is the build quality , its notch better than mikuni ( hence the price ) the main thing is that keihin uses roling bearings for the slide = smoother operation and longer life , ( no slide sticking on highly tuned engines with big vacuum ) . But for the money and easy fit + easyer jetting the TM 40 wins for me , ( if the FCR was a straight fit that would be different story ) .

Whoa hold on Maddy,

I have seen straingthforward FCR-kits for sale, drop-in fits - with of course the always-wrong jetting, nothing new in this respect.
So there you go, your wish may come true.

I have researched it mate , they say it fits straight in but id does not the FCR 41 is just too big and you need to mod few things and have it sitting in angle , plus i am not going to butcher my fuel tank , i rather go for the little fella mikuni

Fuel tank would have to be modified.

Cam chain auto tensioner will have to be modified.

AURORA wrote:
Fuel tank would have to be modified.

Cam chain auto tensioner will have to be modified.

Well, it seems from your feedback to be easier to fit the TM 40...and cheaper.

I would fit stock carb......