Carb Questions !!!!

[afew400ex]

Ok, here's the issuse....
I'll try to give as much details as possible to try and speed up the help from you guys.
I bought a 2000 400ex that is stock, except for aftermarket k&n knock off air filter, he had it for a few years with no problems until carb started dumping fuel during wheelies. so he parked it (outside, bad move). that was 2 years ago.
I brought it home and started messing with it.
Cleaned the carb, complete tear down, pulled needles, bowl, air/fuel ratio screw, main jet & slow jet.
All looks good, no debris or bent parts.
clean air filter, new gas, cleaned plug.
now heres where it sits:
Will not hold idle, backfires real bad under 1/2 or full open chock, & won't run unless I rev it up at least 1/2 throttle.
the idle srew is maxed out, the pilot screw is 2 1/2 turns out & slow jet is 1 1/2 turns out. I also tried to run it with slow jet bottom out(no turns out) Plug is blackish, little wet. But it will fire up under full chock with a little gas(1/8 throttle)

ANY IDEAS ????

[CJM]

You most likely have a bad float and or bad float needle.

All your symptoms point to it being one of the above.

[afew400ex]

I checked the bowl, submerged it in water, no problems found. But I'll double check. I ordered rebuild kit. So bowl needle will get replaced.

[powerbomb400]

Well the black sparkplug is tell is getting too much fuel.

[buck440]

if i'm correct if you do a wheelie it's normal for gas to pour out the overflow. does it on my dirtbikes and quads.

[CJM]

^ This is true, but the rest of the symptoms point to a bad float, a float most likely stuck open dumping too much gas in.

[afew400ex]

Originally posted by powerbomb400
Well the black sparkplug is tell is getting too much fuel.

Yea, it is getting to much gas... Not sure why it bacfires under 1/2 or open throttle

[afew400ex]

Originally posted by CJM
^ This is true, but the rest of the symptoms point to a bad float, a float most likely stuck open dumping too much gas in.


I will pull the float out in a day or so when the kit get's here.
Hopefully I missed something simple like that when I put it back together last time.

[afew400ex]

Originally posted by buck440
if i'm correct if you do a wheelie it's normal for gas to pour out the overflow. does it on my dirtbikes and quads.

My other 400ex leaks a little gas( small stream) when I wheelie.
But not a full stream or pours out.
My other 400 has been jetted, k&n filter, aftermarket ignition.
not sure if that should act any different than stock carb.

[CJM]

Backfiring in your case is due to a rich condition.

[buck440]

idk man carbs is one thing i will never understand, kinda like a vagina. don't know where to begin.

[afew400ex]

Originally posted by buck440
idk man carbs is one thing i will never understand, kinda like a vagina. don't know where to begin.

LOL.....

[Matt150]

check to be sure that your pilot jet is not plugged

[afew400ex]

Ok carb has been completely rebuilt...
All new jets (stock) new seals, bowl checks out perfect.semerged for 10 mins in water, no bubbles or leaks into bowl.
Everything adjusted per factory settings, pilot screw 2 1/4 turns out, air cut-off holds suction.

AND !!!!

Still running like crap.
Kinda hold an idle under full chock, but at 1/2 and full open chock, carb still backfires and dies. plug goes in clean and shiny, comes out black and carbon filled( to rich?)
I can't adjust the pilot jet while it's running, won't run under it's own idle.

I did find one other thing. The carb insolator/intake gasket dry rotted and comes off the intake VERY easy. so I ordered a new one..

Any other ideas where to go now ?????