OK, here's the deal. You need to make sure the idle 'pilot jet' hole is clear. I checked this on 2 bikes tonight with instant results.
This hole is facing the motor on the inside of the carb body. It is below the 2 holes on the brass tube that goes through carb. I poked this with a piece of wire brush, then sprayed cleaner in the tube tube under the jet. If you do this with safety glasses on, you should observe some spray out of all of the holes.