Cheltenham-based engineer Dave Lee is an Excelsior Manxman fan, of that there’s no doubt. This rare 500cc is one of a quartet of the high quality cammies that Dave owns, with among the others an ex-works 250cc example. Coming from an Excelsior-enthused family, Dave inherited his Manxmen from his late father. Lee senior had owned this 500cc version for 40 years, it taking five years to be restored. 

The Manxman was designed as a direct replacement for the complex four-valve twin carb Mechanical Marvel, on which Syd Gleave won the 1933 Lightweight TT. However, after that performances dropped off and a rethink was ordered.

More simple design
What emerged was the Manxman, an altogether more simple design, first shown at Olympia 1934, in 250 and 350cc sizes. It proved, capable of spirited performance, particularly in 250cc form, claiming a first big win when Denis Parkinson won the 1936 Lightweight Manx GP, the first of three successive victories for the Manxman/Parkinson combination. And proving that old adage ‘win on Sunday, sell on Monday’ demand increased.

However, Excelsior had a problem – Blackburne, which had been building the engines (incidentally, it also built the Marvel engines), announced it was stopping at the end of 1936 so Excelsior, due to having financed much of the engine R&D, claimed the drawings, patterns, dies and tooling and brought the project ‘in house.’

By then, Excelsior had launched the 500cc version, originally labelled the F14, which appeared for 1936. Specification was pretty much the same as the smaller models, but with bore and stroke at 82 x 94mm. The 1936 500cc model was only intended as a roadster. In 1937 it became the G14 and was joined by the G15, a ‘supersports’ variant with a bronze head, higher compression ratio, close-ratio gearbox and qd lights. The 500cc model was to go through H (1938) and J (1939, as Dave’s) incarnations, while a K14 (1940) was listed too.

Meanwhile, the smaller version continued to excel on the racetracks (although the one and only 500cc racer was prepared and used by Tyrell Smith in the 1939 TT; it retired) but other Manxman successes included Parkinson’s MGP wins and TT runner-up spots in 1936, 1937 and 1938, while Tyrrell Smith also won the 1936 European Championship, thanks to victory in the German Grand Prix. It all proved vindication of Excelsior’s decision to ditch over complication in favour of simplification.