No vacuum= broken piston rings, valve stuck open, blown head gasket, cracked head, hole in piston, bad seal between intake manifold and heads bad seal between carbs and intake manifold, broken vacuum lines or just not connected and probably a couple of things I have forgotten over the years.Now with that said, go back to before you pull carbs and set your valve clearance. did the bike run ok? If so then you know the problem has something to do with the reinstall of everything you removed. I still say the carbs on that side of the motor were not fully seated in the intake boots. the jets can be plugged, the carbs can be way out of sinc and you will still have vacuum. the problem is an air leak.