Thanks for the ideas.
In the next few days I'll tackle the throttles. My gut says the problems are in the throttle. You know how you can bump that little cable and make you think the motor is wrecked? That's what it feels like.
If that doesn't work, I'll truck it to Mischlers BMW in Beaver Dam.
As hard as yesterday's ride was, my bike got me home. While we were trouble-shooting, for a little while we ran the bike on one cylinder. I'm certain that if I had been in the middle of nowhere, it would gave gotten me home on one cylinder.
A non-rider friend suggested I buy a new bike. They don't understand that this bike has been from Alaska to Argentina, and this is the first time I've had trouble.