Hi Ned,
I've never worked on a Japanese motorcycle, but it would be hard to find a simpler bike to work on than an airhead BMW. I'm talking about the periodic maintenance, not major jobs. If you found a post '81 model, with electronic ignition, then about all you have to do is change fluids and check/set valve clearances, as the timing never seems to change. An owner's manual tells how to do that stuff. Many of these bikes are old enough to accumulate some problems, but that would be true for any make of motorcycle.
Good luck in your search!