A Brief History of the Marque
Achille Fusi was originally the Italian importer of FN motorcycles.
He produced his own machines under the RAS brand and after Fusi's death in 1932 the company was run by Luigi Beaux. In the mid 1930s Fusi bought the CF factory and began building machines which utilized many FN components and powered by 175cc to 500cc JAP engines made in Italy under licence, and by it's own 175cc engine. There is also a mention of Frera engines being used early in the piece. ¹
They produced the M250 OHC machine with a facecam engine of which was developed by CF, in 1935. The Slater facecam design originated in England and a similar engine was developed by Soyer in 1928.
By 1937 they were producing a range of motofurgoni with mostly 500cc JAP engines.
In 1941 Fusi introduced the 4-speed OHC M 25 CFS. When production resumed after WWII, this model formed the basis of production, now once more named CF.
A sports verion, the CFSS, was capable of 135 km/h. There was also an M56 SBB 448 cc OHV, the M25 FFT 248 cc SV, and several others.
Sources: Henshaw, Moto-collection.org et al