Ok, I think I'll make me one of those DIY manometer things to do the sync. Those cheap vacuum gauges I see on Amazon and places seem to jump around too much and a lot of people recommend against them.
I think I may have discovered what is going on though. I took her out for a short 1/2 hour ride today and got her good and warm. What I discovered is that when I blip the throttle, it pretty much comes right back down (to ~1500 rpm), perhaps with just a very slight hang. But - when I rev her up and take my hand off the throttle, letting it snap back by itself, the RPM drops down to ~1000, perhaps slightly less! Give her throttle and then back to idle with my hand on the throttle, and it will only return to ~1500 rpm.
So it apparently is something with the linkage/cables. I did notice that the return cable looked a bit looser than it had before disassembly, so that most likely is the culprit. Other than the idle RPM though, the bike has been performing flawlessly... quick throttle response, plenty of power throughout the rpm range, and I took her out on the Interstate and hit ~90 mph smooth and easy. I need to consult the manual to see what is needed to adjust those cables. I also noticed that the rpms will kick up a bit when the front wheel is turned all the way to the left - further indication that something may be going on with the cables.
I'd still like to tune the carbs a bit, and I did get one of those "D" sockets a while back so I could do it. Now I just need to get one of those round 'finger ratchet" things to make turning them easier.
And to think that all of this misery was completely self inflicted!
Cheers,
Brad
