Choke problem......

[bborntofly]

I'm having problems with my yzf450's. They haven't been ridden in over 4 months. Now when I start them up they will run fine as long as the choke is on. The minute I take the choke off they start backfiring and running real rough. Its almost like some safety brake switch is on or something. Please help......

[ZRider400]

sounds like its lean. Try richening the air/fuel screw.

[Toadz400]

Has the temperature changed quite a bit since you've ran them? It's getting into the winter months so depending on where you are you're probably running a bit lean.

[woodsrider4ever]

clean the carb out mabe eaving replace the main jet and needel

[bborntofly]

Thanks for all your help, but someone said to richen it up a bit. Where is the air fuel mixture at to do this. And how much do I turn it to richen it up????

And how hard is it to take the carb off and clean the hi and low jets out?

[Toadz400]

Get a manual, changing out your jets is not hard at all. I would suggest bumping up the main jet and richening up your needle by dropping the clip at least one position. Your fuel screw should be at about 2 or 2.5 turns out for the cold weather.

[SandShark400]

well first make sure you dont have it backwards! Starts fine with choke off then you choke it and it could backfire and die. Get iT?

[Toadz400]

Originally posted by SandShark400
well first make sure you dont have it backwards! Starts fine with choke off then you choke it and it could backfire and die. Get iT?

I'm sure he doesn't have it backwards. The temperature has dropped as it's now getting into the winter months so this is expected when jetting is not changed. All he needs to do is richen up his main, needle, pilot and fuel screw and all should be fine and dandy. It'd be helpful to know the elevation, temperature, mods, and his current jetting though to give a somewhat accurate starting point for winter jetting.