yes, yes. I cleaned all the jets very carefully, as well as the fuel screw passages. I have checked my valve lash. I just didn't know if what I set 'em to was right. Also- I agree that the valves can be damaged by being imporperly set, but This would not cause my particular problem, because the bike used to run with the compression release pulled... when I went to start it.
My valves are set to:
intake: .004
Exhaust: .006
I finally got a hold of the potential answer!
a few days ago: bike ran
Now: no run
I removed the supertrapp endcap and plates/spark arrestor from my pipe to clean them in solvent. When I put the discs back, I think I overtightened them, which might cause excessive back-pressure... This would explain it. If exhaust cannot escape the pipe, the engine'll start and then stall as pressure builds. also- it would explain the nasty backfires and kicking-back of the starter. The clanging I heard (only after the engine tried to run) could be the exhaust pressure from the pipe opening the exhaust valves and flowing back into the cylinder, due to the excessive pressure...
Tomorrow, I'll yank that sucker off and give 'er a kick.