fcr 39mm carb... need help fast!

[taylorman08]

hi,
i'm going tu purchase a fcr39mm carb for my 400ex and i want to know if a yfz carb would fit on it? I heard that the 450r cables would fit well but i'M not sure... Help me please!

[komatsu kid]

i dont know if the yamaha carb will fit,but the 450r cable you can use on the fcr39 thats what i'm using

[Doibugu2]

The YFZ cable does fit, but Cobly from C&D said the R cable is even better.

[taylorman08]

How a cable can be better than another else?!

[RIDER11X]

Originally posted by taylorman08
How a cable can be better than another else?!
Maybe it's the length of the cable housing....:ermm:

[cals400ex]

i would have to say the yfz cable is a perfect fit. the length is perfect and the price was good.

[TORO1968]

I agree with Cals... The YFZ cable works perfectly, probably even better than the stock cable with the stock carb.

-Jordan :)

[taylorman08]

What did you do with the TPS cable (throttle position sensor) that is on the yfz carb?

[cals400ex]

we are not usign the yfz carb. we are using other fcr's. i actually didn't know the yfz came with a throttle positioning sensor, but the 450r does. the throttle positioning sensor on my FCR 40mm i just pluged it up. you don't need it.

[honduh440]

get the fcr off the honda dirtbike "crf450f"

[cals400ex]

Originally posted by honduh440
get the fcr off the honda dirtbike "crf450f"


yes, this is the fcr 40mm. it is a pain to get hooked up because it is different length than stock and it rubs on the gas tank too.

[honduh440]

mine is a 39mm of the dirtbike. have they changed them to a 40mm on the bike recently? yeah everyone told me about the lenght and having to get an adapter but i just unbolted my airbox and moved it forword into the right position and rebolted it down. and yeah the gas tank sits on it but doesnt hurt it

[cals400ex]

no, yours is just from a different bike if it is a 39. the crf450 dirtbikes come with 40mm's. others i believe come with the 39. the 40's are supposed to flow quite a bit better, even better than the 41's. they are just a newer generation carb.

[RIDER11X]

Originally posted by honduh440
mine is a 39mm of the dirtbike. have they changed them to a 40mm on the bike recently? yeah everyone told me about the lenght and having to get an adapter but i just unbolted my airbox and moved it forword into the right position and rebolted it down. and yeah the gas tank sits on it but doesnt hurt it

Caution: Rubbing the tank, is a future hole in the tank, leading to a future fire! Can you tilt the carb to one side? Will that help?

[cals400ex]

Originally posted by RIDER11X
Caution: Rubbing the tank, is a future hole in the tank, leading to a future fire! Can you tilt the carb to one side? Will that help?


yes, you can tilt the carb a bit. it will stilll rub though. i think i may take a hack saw to mine. i believe you can take a good chunk off that serves no good purpose.

[sampleez]

about how much would you say the carb will make on my bike. ie(stock piston to 11:1; from not ported to ported; stock cam to better cam; etc)

[sampleez]

and what about a 37mm fcr off of a yz250f, i know it wouldn't be as good as a 39/40mm, but i know it would be better than a stocker.

[RIDER11X]

Originally posted by cals400ex
yes, you can tilt the carb a bit. it will stilll rub though. i think i may take a hack saw to mine. i believe you can take a good chunk off that serves no good purpose.

Maybe if you completely empty the tank, and fill it with boiling water, you can indent it where it needs to be. I've heard of tanks being shaped this way before.:cool:

[cals400ex]

sam, i have no idea how much that carb would help. the 39's would provide much better throttle response. it would be good for around 2 horsepower if i had to guess.


i could possibly do that to the tank. the part that sits up high is i believe where the hotstart cable goes into the carb. since i don't use the hotstart, it doesn't need to be there. i will think about it more.