Slowly going up through the rpms while I am sitting in neutral reveals a cough about 2K rpm. I thought it was only with it cold, but it seems to do it when warm. I don't seem to notice it when I'm running. Is this have to do with the needle setting or the idle/air adjust circuit? I have the MBRP slip-on with the dyno jet kit. The needle setting is 2 down from the top, air screw is 2 1/2 turns out. The plug is a nice tannish color so it seems I have things close. What would you guys recommend? (other than getting rid of the MBRP)

 

I've not had this problem with my DS. But I did have he exact same problem with my 400ex and it was the neddle position. I ended up having to raise the needle 2 positions. Or lower the clip however ya want to say it.[img]i/expressions/face-icon-small-wink.gif[/img]

 

So at about 2K that is the range for the needle not the idle circuit?

 

The circuit the carb is using, is related to the opening of the slide, and not rpm. Roughly the pilot circuit is for idle and a hair past, then the slide cut out takes over til 1/4 throttle. So depending on how far you opened the throttle, will determine which circuit. I would think youd hit 2000 on the pilot circuit, in neutral.