The Terminator speaks!!!
...and the mystery deepens.
'Hooked up an old battery with jumper cables, poured some fuel in the fuel line (tank is off), and shot some starting fluid in the spark plug hole. Replaced plug, hit the starter, and it fired right up and idled as long as I kept adding gas to the fuel line. This is good news!
Next I will try putting the tank back on to see if it will do more than idle.
I am puzzled by the fact that the bike started right up, however. Maybe the PO completely fixed the bike with the head swap?? I took the valves out of the original (97) head, but I can see no damage. The head and valves look fine to me. So what happened to the bike to make it sit unrepaired for years? Maybe something will become apparent when I ride it. Maybe I'll never know!??