Doug Hele (13-07-1919 – 02-11-2001) designed and made two desmodromic heads in 1957.
Work continued in 1958, and in 1959 a 500 engine was taken to the TT. Bob McIntyre tried the desmo in TT practice but reverted to a conventional engine for the races. “The desmo programme showed promise but we didn’t have the time or resources to recognise its potential. There were too many other things going on at the time….. The desmo project died a quiet death.”
Source: “Save Surtees’Single : Works Desmo Norton” in : Classic Bike; May1998, p. 28 – 32
Hele: “We spent a lot of time making different cams, but we never got more power from the desmo than a standard engine would produce.
More time was needed on the engine, but that is one resource that development engineers are always short of.”
Source: “Doug Hele : Engineering to win” in : Classic Bike; April 1987, p. 26 -31 (p. 63 continued)
Source pic of engine drawing: das Motorrad ; 1959, Heft 13
[Classification = Group 9]