The three model range from 1919 continued with minor variations to the
3½ h.p. models.
A new, Marston patented, leaf spring suspension was introduced for the
front forks of the 3½ h.p. models along with a rear drum brake. The front
wheel retained a bicycle-style stirrup brake.
The 3½ h.p 'Sporting Model' was differentiated by lower
handlebars, footrests rather than footboards, and a higher compression
Engine and Gearbox
The magneto drive cover takes on its traditional lozenge shape. The
engine was given larger cooling fins.
* Robert Cordon Champ, 1980, 'The Sunbeam Motorcycle'. Haynes Publishing.