Like BSA, La Fabrique Nationale d’Armes de Guerre (‘FN’, for short) began as a munitions manufacturer, turning to the production of motorcycles in 1900.

Today the Belgian company is best remembered for its sensational four-cylinder models, the first of which appeared in 1904 and was first exhibited publicly at the 1905 Paris Cycle Show.

Designed by Paul Kelecom, the FN was the world’s first practical four-cylinder motorcycle, its smooth, almost-vibrationless operation setting it apart from rival singles and v-twins.

Advanced for its day, the 362cc air-cooled four featured ‘atmospheric’ inlet and mechanical (side) exhaust valves, a robust five-bearing crankshaft, individual crankcase oil wells ensuring adequate lubrication for the connecting rods, and reliable Bosch magneto ignition.

Shaft final drive was another innovation.

Supported on ball bearings, the driveshaft ran inside the right-hand frame member to a bevel gear on the rear axle.

At first there was no clutch, the direct-d...