The Classic Motorcycle
To illustrate the technical variety and innovation of the 1930s, 250cc GP design was so diversified during that period that six different engine types were used by the winners of the last seven prewar Lightweight TT races. These were: 1. Twin-carb four-valve radial–Sid Gleave’s 1933 Excelsior Mechanical Marvel. 2. Single-carb fourvalve radial–Jimmy Simpson’s 1934 Rudge. 3. SOHC two-valve– Stanley Woods’ and Omobono Tenni’s Moto Guzzis in 1935 and 1937 respectively. 4. Pushrod OHV twovalve–Bob Foster’s 1936 New Imperial. 5. Supercharged twostroke split-single– Ewald Kluge’s 1938 DKW. 6. DOHC two-valve– Ted Mellor’s 1939 Benelli.