400ex won't idle

[400exbat]

My 400ex won't idle. It starts good and seems to run well but the rpms just drop off and the engine dies when I let off the throttle. It's got a K&N filter and a FMF megamax exhaust. The guy I bought it from says the jets are stock. Anyone have any advice? Should I mess with the idle mixture screw or is the inability to idle a symptom of some other problem? Thanks in advance.

[Jimmy Lee]

Try the Idle Air Screw its probably located on the right side of your carb...Go two full turns with it and if it doesnt idle then have it checked out by a pro!
JJ

[REC]

Hey 400exbat, there is a idle speed adjustment on the left hand side of the carb., right infront of the yellow choke lever. It is a silver knob that you can adjust with your fingers. Screw it in to increase the idle, screw out to decrease.
Hope this helps.
:)

[Tommy 17]

if those don't work try the throttle cable where it comes out of ur thumb throttle assembly...

when i put on my new cable it wasn't adjusted right up there and it wouldn't idle...

[nakomis0]

Originally posted by 400ex21
if those don't work try the throttle cable where it comes out of ur thumb throttle assembly...

when i put on my new cable it wasn't adjusted right up there and it wouldn't idle...

Thats the way I do it.:)

[400exbat]

Thanks dudes! I'll try those adjustments and let you know how she runs.

[400exbat]

I tried all your suggestions and it still doesnt idle at all. What should I do next?

[Lorduss]

Tryed warming it up yet? i mean, hondas allways konk on a cold start, stay on the throttle back and forth untill the engine warms up, run it around for about 15 min,
it should idle then, if it doesnt, increase your idle speed then,
if youve been repiped, you should have been rejetted, i dont know much about jetting but that might be your prob, whats your elevation ? that plays a role to.
if all else fails, take it to a pro, but first, talk to the guy you bought it off of,