Whittaker Howarth’ (Manchester, UK) watercooled 500 cc. threecylinder two-stroke turbo motor with (3) desmodromically controlled inletvalves.
[Classification = Group 7B]
Source: “Radmarkt” nr. 2075 p. 12-14 (28.02.’31) This 499cc engine had a 4 speed gearbox with chain final-drive