i have a 2000 honda 400ex and it will not idle on its own. i have taken the carb apart numerous times, cleaned it well, iv blown air through it, iv done everything i can think of. im not sure if it has something to do with the air/fuel mixture screw or not. if you have an ideas i could use some help because i dont know what else to do.

 

When is the last time the valves were run?
Have you cleaned the pilot jet? Do you know what the pilot jet looks like?

 

Is your quad stock, if not what is your current jetting?

 

yes my quad is stock, iv cleaned the carb many times and it doesnt seem to help. do the jets just go bad? or could it be something more tecnical?

 

and drturbo, yes i have cleaned the pilot jet, it is right next to the float, iv taken the carb all the way aprt and cleaned it throughly. but im not sure what you mean by my valves being run?

 

When was the last time the valves were adjusted?

 

I would change out the pilot jet to a 40 or 42 and see if that helps any, also did you ajust the idle screw to see if that helps any, your air fuel screw should be 2.25 turns out i would leave it there considering you are stock. Also have you tried using the choke? I would start with the idle screw first then try the jets there only a couple bucks get the keihin ones.