How Am I Running Rich?? Please Help

[tahoe97]

I am running stock main jet and needle in stock position.. I have tried the pilot screw settings from 2 turns out to 3 turns out.. I have uni vents in my air box and and running a pro cicuit t-4..

I keep on fouling plugs .. it doesnt take but probably 25 minutes and the plug is fouled it is a dark dry black so i am assuming that means i am running too rich..
How with the air box vents and the pipe could the bike be running rich?? is this normal i mean my friend jeted up his 400ex.. Why would mine need to go down?

right now i am in the process of adjusting my needle one notch to make it more lean and plan on running the pilot screw 2 1/2 turns..
This is all i know to do.. I would apreciate any input on why with the mods would the bike run lean and also woudl like to know if i am doing the right thing or what i need to do

[Guy400]

Ben didn't have us submit tech articles for nothing:D
http://www.exriders.com/techarticles/sparkcolors.html

[toby400ex]

Take the thing apart and check the float valve seal. Mine was causing my 400 to do the same thing, only it was fouling them quite yet. The seal could just be dirty or you might need to replace it. If it is bad it will let the bowl overflow and make you run rich. It also makes the carb dump way too much gas, mine would dribble all over the floor when i just shook it by the bars. I got a new one on the way. They only cost about $15

[White_Knuckles]

By "fouling the plug" does it stop firing to where you have to remove and clean it or are you saying fouled by the fluffy black color? You're right if anything you should have to go up a couple main jet sizes to compensate the pipe and airbox mods. I'm sure you've checked the air filter to make sure it's clean. The idle (fuel screw) and mid-range (needle clip) settings could not cause such a drastic effect so eliminate their adjustments until you get the primary cause isolated.

Float overflow can cause excessive fuel as Toby400ex suggests. It may be failing float needle and seat assembly (usually just the rubber tipped float needle under the float arm). Check the float arm as it may be binding or got bumped during disassembly. Make sure your choke is operating properly and goes fully open. You may pickup a couple main jets as when you correct the current problem you will go lean from the mods. Turning out the idle mixture fuel screw is making it richer.

[tahoe97]

I was thinking maybe it could be the white brothers CDI box i have in it making not fire right or something?? anything think that could be it??

And when i say fouled the bike starts running funny then it gets to where it wont even crank....

then i take the plug out and its a DARK dry black

[honda_man_300ex]

Hey guys,

My 300ex is doing the same thing as toby said his was but the plug never fouls like that. all i got is a dg pipe and an air filter and the motor bored .060 over with the wiseco high compression piston. i put a dial a jet on the system but it will not fix jetting problems. if i leave the carb air lines down like they are supposts to be fuel just runs out of it. got any thing???

Craig Foster

[swamprider7]

if i leave the carb air lines down like they are supposts to be fuel just runs out of it.

This sounds like your floats are sticking. Did you try cleaning your carb? Sometimes dirt can get in there and make the floats stay stuck open. Hope this helps.