designed by walter moore, the norton cs1 engine appeared in 1927, based closely on the es2 pushrod engine and using many of its parts. moore was hired away to nsu in 1930, after which arthur carroll designed an entirely new ohc engine destined to become the basis for all later ohc and dohc norton singles. (moore's move to nsu prompted his former staff to quip nsu stood for "norton spares used") the norton racing legend began in the 1930s. of the nine isle of man senior tts (500 cc) between 1931 and 1939, norton won seven.