Sparks Racing FCR Carburetor Kit

[silenpro]

did anyone try this carb is it worth the money??? :ermm:

[zrpilot]

Yep I tried it and could not get my 400EX to run correctly on it.

I had a Sudco 39MM FCR on my 416 EX and had issues with it. Tuning it was a pain. My 400EX running the FCR was real finicky about things like accel pump timing and duration, main jet, needle, and it HATED to be smacked opened and always had a bog when doing so. There are people here that like the FCR and have had good luck with the carb, I did just had trouble. Mine runs much better with an '04-'05 450R carb (non-FCR type) and there is alot more experience on the boards here with that style carb.

[silenpro]

k , i sent u a pm about the adpator plate, do you still have any?

[whosyourdaddy]

i have a 450r (05) carb on my 400ex--the power boost and
throttle reponse was greatly improved.
my son put on the sparks fcr 39mm racing carb--the power boost
was amazing. he will leave me in the dust.
sparks sends the carb already jetted--all you do is install and
adjust fuel mixture to fine tune.
if you can afford the $510.00--do it!!!!!!!
you won't be disappointed

[drew416ex]

I have one on my 440 stroker and couldnt be happier with it. It wasnt hard to tune at all. It was worth it to me.

[zrpilot]

For those of you who have an FCR, does yours bog or stumble when you are riding it at say 2-3K RPM and hammer the throttle?

Be honest, I'm just curious if I had bad luck with mine or this is a common problem and it does not effect your riding? Or maybe your able to "ride around" it?

Thanks

[drew416ex]

Mine did, and then I moved the clip up one notch lowering the needle and it went away.

[zrpilot]

Originally posted by drew416ex
Mine did, and then I moved the clip up one notch lowering the needle and it went away.

Thanks for the honest response!! I moved my needle up, down, over, under and every where I could think of... LOL.

I even tried (3) different needles, different AP housing, Adjusted ap..

I even tuned the main on a dyno......

I just could not get that blasted bog to go away....ARGHH

[NacsMXer]

I bought my FCR 39 through Sparks several years back.

To be honest, if i'm just putting around at low speeds and quickly pin the gas it will bog out a tiny bit.

However, this has never affected me during normal riding. I guess it's the way I ride, but even when I go WOT it doesn't bog out on me before I hit a jump or something like that.

I've found that if you "roll into" it quickly, rather than jabbing the gas, you completely sidestep the hesitation. I even asked Curtis Sparks himself about this back when I bought the carb, he told me the same thing to roll into the throttle.

The hesitation has been proven to be caused by a quick over-rich condition when you pin the gas quickly. The accelerator pump is simply too powerful and works too quickly for the 400 motor to handle in that quick instant. I've seen accelerator pump "mods", the Boyesen Quick Shot, etc. but never tried any of them because the hesitation never caused much issue for me.

I got my FCR running pretty much perfect after getting the quad on a dyno to check out my A/F's. The carb offers so much throttle response it's insane. Along with the HRC cam, revving my engine you would never think that it had a huge +7mm stroke on the crank....this thing revs lightning quick.

That's my take on the FCR...it is notorious for the off-idle bog but it wasn't exactly designed for the 400EX either. You sort of have to take the good with the bad and see if you can tune it the best you can.

[zrpilot]

Originally posted by NacsMXer
I bought my FCR 39 through Sparks several years back.

To be honest, if i'm just putting around at low speeds and quickly pin the gas it will bog out a tiny bit.

However, this has never affected me during normal riding. I guess it's the way I ride, but even when I go WOT it doesn't bog out on me before I hit a jump or something like that.

I've found that if you "roll into" it quickly, rather than jabbing the gas, you completely sidestep the hesitation. I even asked Curtis Sparks himself about this back when I bought the carb, he told me the same thing to roll into the throttle.

The hesitation has been proven to be caused by a quick over-rich condition when you pin the gas quickly. The accelerator pump is simply too powerful and works too quickly for the 400 motor to handle in that quick instant. I've seen accelerator pump "mods", the Boyesen Quick Shot, etc. but never tried any of them because the hesitation never caused much issue for me.

I got my FCR running pretty much perfect after getting the quad on a dyno to check out my A/F's. The carb offers so much throttle response it's insane. Along with the HRC cam, revving my engine you would never think that it had a huge +7mm stroke on the crank....this thing revs lightning quick.

That's my take on the FCR...it is notorious for the off-idle bog but it wasn't exactly designed for the 400EX either. You sort of have to take the good with the bad and see if you can tune it the best you can.

Thanks NacsMXer. You describe similar problems that I had on my FCR very well. I appreciate the comments.