I cleaned the advancer on the red 90 and it idles correctly now. The advancer was not sticking that I could tell with it in hand, but it was sticky with old funk. I also tried all three of my 90 carbs on the red 90 since it was running so well. The yellow 90s carb was the least favorite but the red 90 ran just fine with it, a little down on power tho. The red 90s carb was second best, definitely better than the yellow 90s carb. The piece of resistance was the knock-off carb that was styled like the 90 carb, replete with high-altitude knob. That carb was head and shoulders over the stock carbs, easily adding to the top speed. I made no adjustments other than idle speed and the bike ran it's best with that carb. Since I'm keeping Barney as o g as possible he got his old carb back and the yellow 90 may as well get it's old carb back. So I'm sitting on this 100$ new carb for now. I may put it back on Barney when nobody is looking. Incidentally the new carbs drain is 6 oclock to the stock carbs 3 oclock, I put the stock bowl on the chow-mix carb for the tests and it worked fine. So if you are at yer wits end with your old carb, try one of the 100$ stock looking carbs from Wincycle and put the old bowl on it for the drain feature.
I also ran the red 90 back to back with the 110 and found the 110 to be a little torquier and seemed to feel heavier with wider bars. I will definitely keep those two bikes and the yellow 90 is on the bubble.