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
Two versions of the 347cc side-valve
model were produced: the Model 1(touring)
and Model 2 (sports).
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.
The Model 7 (596cc) side-valve machine continued to be
produced, aimed at side-car work.
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.
Frame and cycle parts
Front forks were 'beefed up' (Robert Cordon Champ's description) 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
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.
Models 80 and 90 were given a 'bullnose' petrol tank.
Engine and gearbox
[text to follow]
* John Marston Ltd., 1927 'Sunbeam Motor Cycles' Catalogue.
* John Marston Ltd., Sunbeam Spare Parts List 1927.
* Robert Cordon Champ, 1980, 'The Sunbeam Motorcycle'. Haynes Publishing.
* Robert Cordon Champ, 1989, 'The Illustrated History of Sunbeam Bicycles and
Motorcycles'. Haynes Publishing.