The Belgian Arms company ‘FN’ was the first to make 4 cylinder motorcycles in 1905. This is a 500cc engine, as big as that in the Gilera, but doesn’t look big because of the small cooling fins on the engine. These and other inline 4’s would usually be limited by the back cylinder getting hot. This bike has no clutch. When you stop, you must stop the engine and then peddle to get started again.