Well, no dice. O-ring in place and accounted for, as is the washer. I rebalanced the carbs and no change. The right carb is not responding to the air mix screw.
On a test ride today, I realized the lean pops on deceleration are only on one side- the left side.
Looks like I'll be pulling them and going through them bit by bit. I was thinking of rejetting up any way. I guess this is a good excuse to try some 48 pilots and 155 secondaries.