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View Full Version : Modifying chassis to fit FCR carb?


Guy400
04-10-2003, 03:00 PM
Guys, I was just told that in order to run a 40mm FCR carb that you've got to modify the EX frame cause it won't fit in there stock? Any truth to this? I've never heard of this personally but I haven't really followed the FCR carb too much. Let me know about this cause a decision has to be made.

Thanks.
CBRSLIDER
04-10-2003, 03:03 PM
Guy,

I don't know about the 40mm but I know that my 39mm fits without a problem. I believe that the 41mm fits the same way as the 39mm. Did you get the 40mm from a crf? I'll see what I can dig up on this.

Ray
Ben
04-11-2003, 01:15 PM
Bump
04-11-2003, 02:40 PM
my lectron wouldnt fit so i put washers under that white thing under the gas tank to lift everthing up so it would fit. maybe you should try that and it may fit
trx400ex
04-11-2003, 02:42 PM
I had to turn my FCR sideways, but i dont see how the frame would ever been in the way unless it about 8 inches wide
crashinmatt
04-11-2003, 04:29 PM
the only thing ive ever heard was the top of the carb rubs the gas tank. so when i put my FCR39 on, i seen it was hittin, so i raised my tank a little .
Ben
04-11-2003, 11:43 PM
Good info guys. :) Can anyone else substantiate that an FCR carb will fit the 400ex as long as you raise the gas tank a tiny bit?
H_W
04-12-2003, 02:43 AM
I just put a FCR 39 on my 400ex and I did not notice it hitting the gas tank. It fit perfect. And wow what a difference it made.
Silverfox@C&DRacing
04-12-2003, 04:40 PM
How does your carb work when it is in sideways..:confused:

You do not have to do any mods to get the carb to fit. some may need a spacer for the fuel tank..
CBRSLIDER
04-12-2003, 05:01 PM
My tank didn't appear to be touching the carb but after several races I noticed that the front allen head screw on the carb was worn. So just watch the clearence between the two.


How does your carb work when it is in sideways..

I was wondering the same thing?:huh

Ray
ChadEXer
04-13-2003, 01:58 PM
Originally posted by fourzerozero
my lectron wouldnt fit so i put washers under that white thing under the gas tank to lift everthing up so it would fit. maybe you should try that and it may fit
That is the same thing I done with my Lectron. I put washers under the white heat shield that the tank sits on to space it up and it worked fine, it kept the tank off the throttle cable anyway but I still had to run it sideways a little. It ran fine sideways. But now I bought the spacer($30 at FBG) that spaces the carb back out from under the gas tank and it sits upright now! And it also makes it where you dont have to take the plastic and tank off to take the slide out to adjust the jetting(needle)! Got to be the easiest carb out there!!
Sandragggen
04-13-2003, 07:00 PM
FCR41 fits perfect.
MIKE400EX
04-14-2003, 01:53 AM
And another FCR41 fits with no issues.
K_Fulk
04-14-2003, 09:39 AM
I just put a piece of cardboard on top of my fcr. But ill try the washer tip. Mine fits fine otherwise.
trx400ex
04-14-2003, 10:24 AM
Originally posted by Silverfox@C&DRacing
How does your carb work when it is in sideways..:confused:

You do not have to do any mods to get the carb to fit. some may need a spacer for the fuel tank..

Why would it affect it, it works just fine, and i dont mean horizontal on its side, just tilted over some....i was told by an engine builder to do this....and no it would not fit unless i spaced up the tank or tilted it.....i think it has to do with where the cable holder on the carb is set too..ive heard fo some people who have had to do nothing, and some who had to modify to fit....
out4sand
04-14-2003, 10:35 AM
My FCR39 fit without a problem as well.
86atc250r
04-14-2003, 11:35 AM
The 39 and 41 FCRs are a different beast than the 40mm FCR from the CRF.

Yes, the 39's and 41's fit fine - some raise their tanks a bit if they've sagged, but that's about all it takes.

The 40 FCR is not such an easy conversion, which is unfortunate, because they're cheaper and better (for our application) than the 39/41 version. I've not tried this conversion myself, but from what I've been told by a couple different people the carb gets into the frame.
04-14-2003, 02:56 PM
Call Rocky Ridge Racing..I believe Ken has the hookup because he mentioned to me on the phone one day about a trick 40mm FCR carb for $325 or so and and that it pumped out more power than both the 39 and 41..:confused: Don't know but he's been in the buisness for along time and knows how ta piss a fowheela off...:bandit:

Rocky Ridge 270-964-2509