Antoni Serra established FNM in 1921 building bicycles, sidecars and motorcycles using Ace, Villiers and JAP engines until 1936 when the Spanish Civil War errupted. The factory was destroyed during the war.
In 1921 the Spanish government was in search of a reasonably priced machine suitable for sidecar use for its armed forces. Inspired by FN's success as a manufacturer of motorcycles for the military, Serra's solution was an inline six cylinder motorcycle.
The design was not adpopted by the army, so the following year Serra created a new four-cylinder machine using an American Ace engine and once more submitted a motorcycle for military approval, which was not forthcoming. It is believed some 12 of the four cylinder machines were built with engines of 998cc and 1263cc capacity, and all went to the civilian market. One of these has survived.
In the early years of production Patria built attractive light motorcycles fited with a four-stroke 175cc JAP engines and two-stroke 250cc Villiers, both with three-speed Sturmey-Archer gearboxes. The JAP had chain drive and the Villiers retained a belt transmission. By 1930 the range had expanded to at least four models including a 500cc JAP.
The Barcelona musuem has a 1929 350cc two-stroke.
There was also a Patria built in Germany
Sources: Gérard Martin and Lolo Martin, both of the FB 1867-1930 Motorcycles group; entre-tubos.blogspot.com; period literature.