Except for the repair/service manual on the right, has anyone ever seen the specific contents of these folders? I mean, how many circuit diagrams can there be? 60, 88, 93 on the #1,2,3 folders means what?
Maybe it's multiple diagrams in multiple languages..
Looks like #1 is Boxer models from '69, #2 from '88, and # from '93. The word "ab" in German means "from". Each book contains info in several languages. Not sure what the fourth book contains, maybe common descriptions, overhaul, specs, etc.