OK, my first problems were: poorly ventilated gas tank and a leaking fuel cock. The bike would start and run for awhile, but only for about ten minutes. The leak wasn't going to keep the bike from running, but I fixed that first (simple stuff-- better gasket, some gasket maker goop) and then vented the cap with a small hole and a rain cover molded from JB Weld putty. Fuel flows freely as it should.
I also cleaned the carburetor and air filter because... well, why not. I also think that I had gotten too much 2-stroke oil into the carb first thing. Cleaned and fully dried before reassembling.
While I was at it, I upgraded the plug wire from the CDI as well as the spark plug itself. Gapped to .020 as recommended by Sick Bike Parts (.018 to .022)
Magneto is clean and dry. Clutch is clean and dry. Fuel filter has been in place since day one. CDI connections are clean.
BUT IT STILL WON'T RUN.
what am I missing? what should I look at next? This is driving me mental because right now all I have is the bus, and it takes two hours to get to work each way... The bike will cut that down to about 40 minutes. Spending 4 hours a day on the bus is screwing with my ability to sleep (because I'm left with about two hours a day to eat, relax, and try to do chores), and my health condition can't take this much longer.