Fouling plugs only when cold, and idle is fluctuating. Carb. Problem?

[Vinny2692]

Yea, i have a 04' yz 125, and when its cold, only when its cold, it fouls plugs, then it warms up and it runs fine. Also, the idle goes up and down. Is this a carb problem??

[philepe]

start with basics.How familiar are you with 2 strokes?Are you warming it up properly before riding?How long do you use choke when warming it up?Are you a letting the engine bog too much when riding,such as in slow tight terrain

[radsdad]

Don't let the bike idle when it's cold. Mine run better if they won't idle at all.

[Vinny2692]

well im very fermiliar with 2 strokes, and i am wariming up properly and riding it properly, but i think i found the solution today, i changed the needle and seat, and leaned the pilot jet and it seemed to fix the issue. Oh, and my main jet is a 450 right now, is that to rich? If it starts fouling again, should i lean that?