1982 Honda Magna VF750C; low compression, idle issues

Here's the thing with valve clearance adjustment; When your bike is new everything is set theoretically correct. With normal wear on the engine your valve clearances will tighten as the valve seat becomes depressed as a result of the valves banging up against the valve seat a few million times. Now when your engine gets hot your valves do not close completely or at the right instant. The engine becomes harder to start, combustion compression and intake vacuum are reduced and your bikes runs tardy.

Yes, check the carbs again and make sure none of the slides is installed incorrectly. Look inside the carburetor throat with the air intake rubbers removed and see that they are all closing when you release the throttle. You would not be the first person to install a carburetor slide rotated 180 degrees from where it should be.

Re: Vacuum intake leak (smoke test) you are very close, if you spray a little quick start (ether) around the intake manifold where there is not suppose to be an intake hole and there is a vacuum leak there, your engine will rev like crazy once it starts to draw starter fluid through any leak.

Update: finally got her running again, and man does she have some power compared to before. With the way she rode I don't think there's anything wrong engine wise with the exception of some bad seals, second gear is a hard shift (clutches are likely very worn) and it could use new plugs and wires. I had to clean the spark plugs off with carb cleaner and very gently using some 400 grit sandpaper to clean the terminals on them. I think the throttle cables have stretched a little over the years, I got it so that it idles perfectly at about 1100rpm if I hold the gas forward (as if to remedy a sticky throttle), but the moment I let go she rides up. From what I can tell it seems to be that the main carbs air luvre is stuck just slightly open. Perhaps I didn't quite put enough turns on the throttle pulley spring when I reinstalled it, though I thought I had it enough as I remember a couple times I accidentally let go and it spun around in my hands giving me some harsh reminders on my knuckles).

All said and done, she still has a few ticks, but she runs strong, and is ridable. Which mean now I am left with the final unfortunate task on the list of seeking to sell her to someone else who could enjoy a bit of a project bike, and perhaps have more luck than me.
Any thoughts on a good solid bike to look for around the $2000 price range? In my area there seems to be an excessive amount of the Yamaha V Star 650's. Not quite my style, but if they are fairly reliable, hold their value and pretty easy to find parts for if be willing to look more at them for the time being until I can find something better.