From a 1977 issue of the Dutch magazine "Motor" comes this photo sent by Ivar de Gier. The MOC Benelli Sei was entered in the 1977 Bol d'Or by Motobecane. It had very aero-looking bodywork which isn't visible in this photo taken while the bike was being worked on in the pits.
Benelli Sei/Motobecane racer Note the two-part spun aluminum wheels, single-sided swing arm, and trigangulated frame using the engine as a stressed member. 106K jpg file