fcr breaking up

[set2crash67]

i just put a 39mm fcr carb on my 400ex. i have a k and n with no air box a hi rev box and a full x-6 system. i put the boyson quick shot on the carb and it was all clean and nice b4 i put it on. it has a 160 main jet. it idles fine and like 1/4 throtle is fine then 1/2 -3/4 it breaks up and is crappy then wide open is fine too. if u go from idle to wide open its fine even wen u hav it liek 1/2 and its breaking up if u punch it its clears up and is fine. what should i do

[terko440]

Have you played with your jet needle positon at all?

yup its probably your needle and main jet

[BLK416]

Raise your needle positon, Move the clip down one slot then see should clear it right up

[Craig02]

I had a similiar problem with mine, if adjusting the clip position does not fix it then you need to get a new needle. Just call up C&D and let them know what is happening and they will send you one to fix it.

[set2crash67]

alright thanks guys..... it not because i have stock bore and internals right. i can still run the bigger carb?

[terko440]

I dont think so, I mean you having the problem from half to 3/4 so if anything you would have problems in the low rpm. But now that you mention that your bike is stock, dont ask for too much or think your carb is junk if you do have problems when you open it wide throttle real fast.

[set2crash67]

no it works fine idleing then if u crack it it works perfect its just like 3/4 it breaks up. thats my only problem but im going outside to adj the neddle and maybe ill mess with the fule screw.

[set2crash67]

ok now i feel really stupid but...... i cant find the needle or clips to move them up to what you guys said. i have both the bottom and the top of the carb off. the top looks like all throttle linkage so im gussing its so where on the bottom? :confused:

[rooster300ex]

if u got acrobat reader this will show ya.


http://www.dynojet.com/pdf/Q107.001.pdf

[Barney]

You are looking at the top of a FCR carb. There is two cap screws
holding a cover on take those out remove cover. Now you can see
a screw that hold linkage for throttle loosen it up open throttle
all the way you will see a nother hex head screw take it out. Npw tip carb over out comes the needle. Move the clip up one to the
square end Now reassemble and try it . If this does not work
try a smaller main jet but leave the needle were it's at. One of these shoud work.

[set2crash67]

thanks guys for all the help and everything....... i took the needle out and yea there is no clip at all so i think that was the problem. lol im getting a whole new needle and clip from c and d so i should be set....... but THANKS ALOT!!! for all the help

[speedy400]

Some fcr needles dont have clips, it not hard to work with... all you'd need to do is put these real small washers under the main clip, they act as 1/2 clip changes, you can get the washers at radio shack, some cycle shops. ect....posted just for refrence.-darren