Walter Moore designed Norton's first OHC engine in 1927, marketed as the CS1. Although successful, taking the fastest lap with Stanley Woods at the Senior TT that year, Moore left Norton to join NSU in 1929, where his efforts were greatly appreciated. He designed the NSU 501 Supersport models, and in 1938 drew up the RK DOHC parallel twin, a post-war version with 110hp achieving a world speed record 330 kph.
