I recently picked up a 1984 K100 for next to nothing and that is pretty much what it's worth at this point. I did manage to get it running but she is smoking like crazy. There was perhaps some Marvel Mystery involved that needs to get burned off.....but she runs! 
I'll be checking here for all the information I can soak up. Been working on UJMs for decades so this BMW....man what were they thinking? I'll figure it out. Probably. ;-)

Hi BoardBandit, welcome. 

What were they thinking, it's hard to believe but I recon there wasn't even any schnapps involved. 

I wish I was in the board room when they were duking this out. I can just picture it, with the Zeitgeist of the times. The traditionalists saying a BMW isn't a BMW unless it's a horizontal two cylinder boxer, the beancounters saying we have to go vertical inline four to survive the UJM competition. Honda beat them to the horizontal four boxer (so going that way might be viewed as a copy) The engineers probably reluctant but forced to agree that four is mechanically better than two. 

Then the brilliant outcome, a horizontal inline four (BTW like the first aeroplane engine) That fits their brief with easy access to parts making it easy to maintain. And a three's even better to boot. And three is a pretty good compromise between two and four.

Hi BoardBandit

to this forum

Hello!

Welcome Boardbandit