OK, I've calmed down...had a few beers and thought this through.

I "rebuilt" this carb six times, but the truth is, what I was really doing for the last five times was just reassembling it with really clean, but defective, parts. So I bought a rebuild kit with new jets and washers and o-rings and now the bike runs sweet. I'm thinking the needle jet and the jet needle were in bad shape.

I have a question though. When the carb was apart, I could screw the tube holding the main jet down tight against the carb casting IF the emulsion tube was not installed. If I put the emulsion tube in, the main jet assembly bottoms out against it before it bottoms out against the carb. Is this normal? It doesn't look right, but the bike runs so well, I'm not inclined to change anything.

Thanks again, guys. Your help with this carb was invaluable.
Eric