Apart from my K1100LT I also have a K75s which was 1st registered in 1986. Slightly modified by me, bought with only 21k miles showing 4 years ago (for £700 only) and has proved to be the most reliable BMW I have ever owned. It now has 46K miles on the clock and just goes on and on. Not prestine by any description, it has taken me over to Europe 4 times and proved to be well up to the task. Economical, reasonably comfortable, especially since I fitted RT bars and had the seat re-modelled. It just goes on and on.
I think BMW made a terrible mistake by not developing the 3 cylinder bikes.
(The development of the K's in the very early 80's had a 3 cylinder 900 on the books for evaluation, but this was changed to the K100)