I bought my blindly...sort of. I went to see it, it wasn't running and I rolled the dice. I paid $1,400 Cdn for an '86 100RT with 60,000 miles on the clock. She is originally from Dallas and ended up back in her owner's hometown of Trenton, Ontario. Nine years out of service. By the time I was done stripping her down and replacing things that needed replacing (or should be replaced) I was up to around $3,000 Cdn. Don't regret a penny of it. I learned a ton, am very grateful for the information and advice offered by these fine and knowledgeable men and women (Inge!) and have ended up with a bike I would be hard-pressed to part with. I wanted to get her naked (can you say that here??) but was so impressed with her fairing, in all but hot weather, that I kept her stock. Bought a naked Guzzi for the warm days!!
If you've ridden a bunch of different bikes you know how different they can be. They all do something better than another brand/ model and therein lies the rationale for collecting a bunch of different bikes. People always ask "which one do you like best?" (Beemer, Kawi or Guzzi). I don't like any one of them "best". They are all different and I love them all!! Last thing - I take a lot of stock in the owner. What kind of person am I dealing with? If he/ she is a bike lover, honest and has a reasonable answer to anything I am asking I go with it. All 3 of mine were kijiji purchases....all 3 bought from good, honest folks. All 3 are gems!
Sorry....one final comment. You are buying a piece of motorcycle history. Do your research and you will be impressed with the origins and rationale behind the development of this bike and with the technological advancements of this machine for its day. BMW is a storied brand with an excellent pedigree. If that ain't enough to get you involved go buy a Harley!!!
Good luck!