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

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?:thumbsup:

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

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

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?

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