I removed the screen indide the airbox on our 250, this helps throttle response quite a bit. The best way to do this is to remove the airbox, less chance of getting trash in the carb. After this I had to go 2 sizes richer on the main jet.

 

Steve154, Hightower is correct.

 

Update: I have removed the screen in the airbox, put the new carb boot on and went to a stock air filter. I moved the clip to the 3rd position on the jet needle per the Dynojet instructions, but I decided to leave the 126 jet in, instead of going to the 130. I set the mixture screw to 2 3/4 turns out. It is still rich. After 5 minutes of running a new plug I took it out and it was jet black with carbon. I then turned the mixture screw out a half turn and it did the same thing. Which way do I turn the screw to lean the mixture? Any more suggestions?

I am also wondering if I should just leave everything alone? The bike starts up everytime with absolutely no problems and seems to be running just fine. Is there any long term problems that I need to worry about here?

 

You need to go down on the pilot. The air screw, or idle mixture screw as you call it, should be where Dynojet says!