My sister just bought a 250EX and its got a full exhaust and has been rejetted but for some reason the the air screw was turned way out? What should be the correct settings for the airscrew and needle for that matter if that is adjustable too? Also is the airscrew the only idle adjustment on those?

Thanks!

 

i have my wifes set at 3 turns out. ran great with the lid off at glamis.

 

There is an idle speed and an idle mixture both. They are the only two external adjustments. Get it hot and set the idle speed on the low side, turn the mixture screw slowly to achieve the highest idle. Reset your idle speed to spec. If it makes no difference turning the mix screw you got the wrong slow jet or it's clogged. Thats the best you can do without a pilot jet or needle height change. Every stock machine will end up a little different mixture screw setting, not to mention your jetting has changed.

 

what about the whole turning your mixture screw clockwise? until it starts to break up..... then turning it back a 1/2 a turn???

which is the best way to adjust the air/fuel mixture? or do I have 2 different things confused with each other?

 

where is the idle screw and the air fuel screw? I know there is a screw on the right side(when sitting on it)of the carb. Not sure what screw that one is im assuming air/fuel though.

 

That'll be ok too DSAPP. That's Honda's idle drop procedure. I've found that most of their products run a little better and are less cold blooded when set just a tad richer than that ala my previous post. Truth is, assuming your slow jet is correct, you will probably end up real close setting it either way. Slowwarrior, I don't have a good picture in my mind of the EX carb right now, but the idle speed will be at the base of where the slide rests inside the carb. Mixture screws usually face straight down on the head side of the carb, in which case turning it out counterclockwise will richen the mixture. Some smaller keihins, like that used on the atc110 will face out, sometimes at a 45 degree angle, right above the float bowl mating surface, in which case they are an air screw, and turning them out will lean the mixture.