Source pictures: “Königswelle : Pohn-BMW R100” In: MO Sonderheft No. 3 : BMW Motorräder, 2000 p. 12 – 23
[Classification = Group 6 A] = Ducati-like system (= from the 1cil. production; beveltwins and beltdrive 2 cil. generation desmos) with forked rocker to control two valves but with a single camfollower on the other side.