I found this better pic june 2020
Vincenzo Azzariti mounted his desmodromic system in 1930 on a 175 cc Benelli motor.
Actually it was the first Italian desmo-system. This bike remained a single copy.
Source: “La desmodromica Azzariti” in : Storia della Motocicletta Gli ultimi anni : Abramo Giovanni Luraschi, p. 261-262
Source picture: Patented Systems
[Classification = Group 1A(1)]
Patent Azzariti