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?

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

  • Similar Content

    • By Rick Mcqueen Art
      A tiny clear rubber tube on bottom of carb.  On bottom sort of on side, by floats, the other end just hanging down.  Was it always like this? Or does the other end go somewhere?  Today after multiple trys with kick, choke on/off ,,,fuel keeps pouring out the tube.  This bike has always been hard to start.   Thanx  guys!
    • By Brock granberg
      I just did my valve adjustments and put my YZ250f back together as far as the valves, shims buckets and cam covers on but I need adhesive for the plastic valve/cam cover and I am stumped as far as what to use and where to get it or even what to call it! Need to get some soon im in need of a ride!
    • By ThatE30GUY
      Hey guys, I bought this YZ85 and came to realise the clutch wasnt working, so I drained the oil (Jet black) and pulled the plates out and cleaned them. I assumed finding a torque wrench would be easier than it has been. Does anyone know how to torque the clutch springs to spec without a wrench? Any insight helps.