Well, it seems I definitely have one of the more difficult patients on my hands...
I broke down and bought another ultrasound cleaner from Harbor freight. Maybe not the highest quality unit in the universe, but the reviews were reasonably good and it only cost me 86 bucks.
Split the carbs and gave the offending unit a serious ultrasonic bath. Multiple times. Heated the bath for the last several runs. Still, the obstruction remains. I may not have allowed it enough heat or enough time with heat to clear it, but it is proving to be difficult. I will give it another shot this evening.
I am running approximately a 1:1 ratio of simple green and water. If anybody has any better ideas for a more magical elixir, I am all ears.
This Motorcycle’s going nowhere until I get this carburetor cleared out. Once again, I have plenty of flow between pilot air jets one and two, but neither of them pass air through the idle mixture screw port. So far, this ultrasonic bath has not changed that.