Just a note to close out the thread.
I took the bike for a spin today and the motor was awesome, I solved the revving issue, and as a bonus unlocked quite a bit more power.
Here's what I did:
-replaced the gaskets on either side of the reeds (one side was just "form-a-gasket" junk - possibly a source of air leaks).
-disassembled the carb and cleaned it.
-smoothed out the slide (had some ridges worn into it).
-set the idle air screw back to about 1.25 turns out (was at ~2.5 for some reason).
-moved the clip on the needle down to the 2nd slot from the bottom.
-smoothed the needle (had some nicks).
-cleaned the reeds, which had some goo on them possibly sticking them shut some times.
-new spark plug.
-cleaned the air filter.
-removed and cleaned the fuel filter on the petcock (has some junk but not too bad).
So now the engine seems to run amazingly well, but about 30 minutes into my ride, a bolt in the rear suspension let go, leaving the top of my shock to just wobble around down there, ending my ride.
Upon closer inspection someone has made some weird suspension setup to use a shock out of something else, and they have a really bad setup that puts way too much strain on a single crappy bolt. So now I've got to re-engineer that setup, but at least the engine is good now