Test your compression if you have not already. I drove myself crazy trying to figure out what the hell was wrong with the carbs on my vt500c and turned out to be low compression in both cylinders by a badly scored rear and broken piston in the front.
If compression is low and you tear into the engine, do yourself a favor and take it apart until you find what is broken. When I did this, I first assumed it was the valves and just pulled the heads and lapped the valves, installed new seals, put it all back together, and put the engine back in the frame. No luck, still low compression. Had to take it all back apart again just because I didn't want to take the cylinders off while I was already one step away, if I had, I would have found the problem(s) the first time.
2010 Honda NT700V
1984 Honda VT500C