According to Massimo Clarke in “La Storia del bicilindrico Mondial 250” [Motosprint; dec. 1990] Mondial developped three different desmo-systems. The first one was like the Delage-system. The two other systems used two two-armed rockers per valve. Unfortunately in this article no more text/pics.
Source italian texts (near pic) : Luraschi, A., Storia della motocicletta: gli ultimi 20 anni, deelS, Milaan. p.263.
On the picture below the well known author of many titles on Italian Classic Bikes Nunzia Manicardi next to the desmodromic Mondial 175.
Source: Manicardi’s new book (cop. 2012): F.B Mondial : La storia vera e inedita 1952-1954
Present owner: Augusto Farneti.
According to Massimo Clark (in an email date 24-05-2013):
“The only Desmo Mondial manufactured, that the desmo system was of the sliding stirrup type (“a slitta”).
The bike was built by Nerio Biavati in via Milazzo (racing department) during the winter 1955-56.
The crankcase is of the type used by Mondial for his racing bikes only from the beginning of 1956 onwards.
So we focus on the Delage type system.
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