Source: Pics private collection H. cloosterman.
Karel Horak daily drove to his work on his home-made 250 cc bevel-driven desmo-engine (1969).
[Classification = Group 4]
Article (in Dutch) about the invention of Karel Horak. This article was published in Strada, the magazine of the Dutch Ducati Club.
English version (draft translation): Horak article Translated English