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Sunbeam Motorcycles

Sunbeam 1927 Models

The model range was reduced for 1927. Sprinting was made illegal on public roads in Britain and the factory dropped its OHV sprint machines. All versions of the short-stroke 499cc side-valve engine motorcycle were also dropped (Models 3 and 5).

Models 1 and 2

Two versions of the 347cc side-valve model were produced: the Model 1 (touring) and Model 2 (sports).

Models 5 and 6

There were also two versions of the 492cc 'Longstroke' side-valve machine: the Model 5 (touring) and Model 6 (sports). The Model 5 had been introduced in 1923 as the 'Light Solo', a short-stroke engine installed in the sportier Longstroke frame - for those who wanted a sporting short-stroke without the standard Model 3 cycle parts. From 1927 the 'Model 5' name was used for the touring version of the Longstroke-engined side-valve.

Model 7

The Model 7 (596cc) side-valve machine continued to be produced, aimed at side-car work. Introduced in 1920, the 4¼ h.p. 600 was soon re-named the ‘Model 7’ and retained the flat-tank styling well into the 1930s, remaining otherwise largely unchanged until 1940.

Model 9

The 493cc OHV Model 9 was produced with a single-port engine, along with its sporting version, the Model 90, with a two-port engine and separate oil tank. The 347cc OHV machine was available only in its sporting Model 80 version with a two-port engine.

Models 80 and 90

Models 80 and 90 were given a "bullnose" petrol tank. "Bullnose" refers to the shape of the tank on the 27/28 models, which was rounded at the front.

Frame and cycle parts

Front forks were strengthened to cope with higher speeds - and after failures in racing, although no failures were reported from road use. The altered forks have parallel front and rear tubes.

In 1927 wired-on wheel rims replaced beaded tyre rims.

The transverse 'coffee-pot' silencer also disappeared from the side-valves, replaced by a pipe curving across the front down-tube to the near-side of the machine.

The side-valves were differentiated by their cycle parts: the inclusion of a rear chaincase and high-level handlebars for the touring Models 1 and 5, and no rear chaincase and lower sports 'bars for the sporting Models 2 and 6.

Sources: sunbeamsidevalve.com, Bonhams, et al.