FCR conversion

Tamas · Nov 16, 2013

It seems that I have found a carburetor off a WR450 nearby. Ive been reading the owners doc for a while now but I would still like to get an accurate answer for what I have to do in order to fit this carburetor porperly. Im mean aside from the throttle and cable, things like jetting?

Cheers, Tom

tourist · Nov 16, 2013

I'd look into getting a jet kit, there exist Berg-specific ones, and because of emissions restrictions the factory has to contend with, plus accumulated experience on part of technically söcapable owners, the jet kits tend to make the bikes run very very well.

Tamas · Nov 17, 2013

I will buy a jetting kit, but for now only the carb. Will it run as it is? Even if not perfectly can I still use it whitout a specific jetting kit?

Tom

ned37 · Nov 17, 2013

i bought an fcr from a kxf250 and just bolted it on my '00 400. runs fine with just an occasional tweak of the pilot fuel (a zip-ty extended screw helps)

Taffy · Nov 18, 2013

the jap needles are very rich on the straight = where you idle so they can backfire and stall when hot. they also run large PJs.

so they generally run OK but rich.

best get a jetting kit then....but I would say that wouldn't I!!!!

Taffy

Tamas · Nov 18, 2013

I am thinking of a jetting kit but that won't be till spring. Bike is going to hibernate during winter time so getting the carb for now is enough. I am also thinking of getting a bash plate or skid plate, any ideas where can i buy one in Europe? I found one in the US but would be better if I get one from here.

Tom

Kayeffess · Feb 8, 2014

I'm wondering what happened with this. I'm also looking at an fcr conversion for my 01 fe650. The wr450 uses a fcr39 as does the yzf. The crf450 uses a fcr41. I'm watching fleabay but not sure which one would be best. I don't ride the 650 balls to the wall. I use it to Dualsport and the occasional single track when I want a workout. I'm sure either carb will need jetting and tuning. Any input on size of carb and or years best suited for the 650 would be great. Thanks in advance.
K

plumbbob · Feb 8, 2014

Send Tamas a PM as he did have an FCR for sale at christmas time. (Great guy to deal with)

I put a 41 on my 02 650, it made a big difference over stock but still rideable on tighter tracks........just had to respect the throttle a bit more.

Carl

bushmechanic · Feb 8, 2014

41s are a good size for 250Fs

43mm isn't to big for 570 RFS

I reckon get the "big" 41mm one ...

also ... maybe ask the guy you got the crank from if he has a spare adapter . .hes using a 40mm carb and also bought a jet kit, if you went 40mm you could compare jetting with him

viewtopic.php?f=7&t=17492

for the jetting main thing you need to do is put a smaller Main air jet in then everything is much easier to understand.

Kayeffess · Feb 9, 2014

Thanks

So the 41 seems the best? They seem to be readily available w/ throttle and cables off a crf450. Any particular years best or changes?

zaga · Feb 9, 2014

Hi my friend

The 39 will do, but for the 650 maybe the 41 would be best. But it will depend on the price you can get them.

Don't know if you can distinguish the production carb from the MX one ? the MX one would be nicer since you have more possibilities to tune it. Anyway both will do it.

The older carbs specially from japs (YZ, CRF .. ) are all MX ones, ktm usually is a production carb. You can distinguish them by the belmouth, the mx is a removable one.

If you have the chance, you should check for the ware on the slide pate and the wheels, that is the most common problem and expensive to change.

:cheers:
ZAGA

Kayeffess · Feb 9, 2014

Thanks

That's what I was looking for. I doubt I will be able to get a look at the wheels as I don't know if I can find one local. I think I will just try to go with the newest carb I can find at a reasonable price.

Thanks
K

zaga · Feb 10, 2014

Hi

When the plate has more wear you can see metal colour on the bottom of the plate (head side, not filter side), because the plate is black.
That you can see in a picture.

:cheers:
ZAGA

Taffy · Feb 10, 2014

I think it goes
YZ400 1998-1999, WR400 1998-2000. Suzuki DR400e all the way. KTM all 520s and 400s 2000-2004 = Mk1 carb

YZ426 and YZ450 2000 until ? . KTM 400 and 525 2005-2006, all huseys 2004-2008. Mk2/MX carb

all CRF450 hondas = proddie carb

this is only a start, perhaps someone knows in more precise detail?

regards

Taffy

bushmechanic · Feb 10, 2014

I have one off a 2010 crf250 r

41 mm and doesn't look like the "mk 1 or 2"

has a stupid shape on the intake side for the CRF boot

fixed main air jet #220

weird thread pilot air jet

remote hot start

stainless steel splash guard baffles in the bowl

removable AP leak jet

fancy spring loaded needle retainer

looks unused came from israel via Ebay $400

i know the drz400 ones and some of the wrs have an anti - pop decell circuit with a diaphram and some other crap

Kayeffess · Feb 10, 2014

This is great info and probably why the Honda carbs go cheap. I'm assuming that a "proddie" carb is the production carb and the least desirable as you can't change bellmouths and other things, such as jets. I guess I'll focus on finding something other than a Honda. I figure anything I get will need a rebuild and jetting for my own peace of mind.

zaga · Feb 11, 2014

Kayeffess said:
This is great info and probably why the Honda carbs go cheap. I'm assuming that a "proddie" carb is the production carb and the least desirable as you can't change bellmouths and other things, such as jets. I guess I'll focus on finding something other than a Honda. I figure anything I get will need a rebuild and jetting for my own peace of mind.

Hi

You can change jets on the prod carb, only the main air jet you can't change.

About adapting the rubber to the bellmouth I can't tell you how hard it is ??

:cheers:
ZAGA

Taffy · Feb 12, 2014

you need to have a plastic ring made to press on the outside of the carb's bellmouth. then the rubber will fit.

it is the MAJ you can't change and also you can't go small enough on the PJ. = 40 is the smallest.
then you have this bellmouth shape you are stuck with so there are three reasons in all.

regards

Taffy

bushmechanic · Feb 12, 2014

from the thread I linked

Noss machine alloy adapter ... looks nice

mopwer said:
My fcr is a mk2 and doesn't have the removable bellmouth so I found this adapter from Noss Machine.

Just grind off the lip on the filter side and check the fit.

mopwer said:
It was a very snug fit so I only used grey sealant so I could still remove it later on if needed. You could use epoxy if you aren't worried about taking it back off.

Doesn't line up perfectly but close enough for the girls I dance with.

Overall it makes it a little longer than the original set up but I can put the adapter further into the boot.

tourist · Feb 12, 2014

(Have heard good things about the Noss adapters for DR-Zed's, which are A) severely under-carbed, B) highly ubiquitous C) a budget bike, so many people are scrounging for all kinds of random cheap FCR's to cram on 'em ... a good test if a part fits like this and works reliably. And people have been happy with their Noss adapters. fwiw.)

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