Mk 1 OHV still in production, numbers unknown, see 1920 for details, it is doubtful if very many of this model were made in 1922.
2 MAG overhead inlet side exhaust. This is effectively the Mk 1
cycle parts with the Swiss MAG engine. Very few were built.
MK 1 Side Valve. This made up the bulk of production for 1922 Records show 79 of this model.
The Mk 1 SV used a JAP 1000cc single camshaft engine. 85mm bore by 85mm stroke giving about 25 brake horse power.
Sturmey Archer CS 3 speed gearbox.
Open diamond frame with Webb or Enfield wheels and now the possibility of Brampton, Druid or Montgomery front forks.
The important change for 1922 was the introduction of the SS80, in fact the SS80 shared many of the design features of the MK1 models. The SS80 used a modified frame that gave a slightly lower riding position. The exhaust was modified to use the famous cast aluminium ‘lamp glass’ silencers along with cast exhaust port coolers.
Power was still provided by a similar JAP single camshaft engine, but there was a new 3 speed heavyweight 4 stud Sturmey gearbox.
introduction of the SS80 was almost certainly a product derived
from racetrack improvements
made from George’s personal sprint bike called ‘Spit and
( Text courtesy Miles Soppet with the assistance of Dave Clark - B.S. Club Technical Historian. )