Now what?

[FutureRacer]

After rejetting, i find out that my 400ex only runs right when it warms up? what jet would this be?
I couldnt change the needle because the guy before me threaded the damn screws out on the carb. anybody know how to get these screws out?
Also, after warming up, if i rev it to WOT when it decreases RPMs itll shoot out white smoke?
Can anyone help me
Is the white smoke a good or bad thing?
Before rejetting, i dont remember any smoke.
Thanks, Kelley

[underpowered]

well white smoke is a bad thing. it is moisture burning. but are you sure it is white, or does it have a blue tint to it? oil smoke is a very light blue which sometimes people accidentally call it white. i cant say wht to jet your quad at without knowing what jets are in it now, what are all your mods. but you will most likely have to play with it some. i would say if it only runs right when warm, you are too lean, try turnign the choke on or taping up part of your air filter and see if that makes it run any better.

[FutureRacer]

Mods include a k and n air filter and a white bros slip on pipe, that is all. I am very confused and am almost certain the smoke is white, how do i get it to stop smoking?
Thanks, Kelley
its not a huge amount of smoke, i just dont want my quad to smoke.

[underpowered]

Black smoke=too much fuel
Blue smoke=oil burning
White smoke=water or moisture.

i still think it is blue and most likely coming from your valve seals. but it is hard to diagnose exactly over the net.

[02440exkid]

ya i would try fixing the cheap things first like valve seals

[FutureRacer]

I went and checked it out and its definetly white smoke, no tint to it at all
HELP
what is its problem?
Thanks, Kelley

[02440exkid]

Well, sometimes it might look white but wut does it smell like?

if it is really white i would run it until the water or moisture get out of the pipe

but u sed it's when the rpm decreases the smoke comes out i think it oil smoke. jmo

[FutureRacer]

Hey guys, i really appreciate ur help, i have a couple questions,
First, how hard is it to replace those valve seals on my own, considering i have NEVER broken into an engine, although i do know alot about them. Also, do i need any special tools?
I still think its gotta be water, but i will look into the valve seals.
My main concern is how come it only runs right when its been warmed up? What jet would cause this?
I think it may be because my pilot jet is not screwed all the way in?
Common mistake?
Thanks, Kelley