Factory prototype of a Brio 91 with water-cooled aluminium cylinder with thermosiphon circuit from a central radiator. It develops 16.3 bhp at 6,200 rpm. Only three units were produced. At that time (1957) it was tested on the Pau circuit. It was rebuilt in 1997.

Photographed at the Museu Moto Bassella Montesa Exhibition of 2021 by Mike Ricketts.

Montesa Motorcycles