Norton 1927 633 cc sv single Model 1 “Big Four”
The model name Big Four was used from 1907 till 1954, when production of all side valve Nortons stopped.
The model was mainly designed as a strong and reliable sidecar machine: in WW 1 many were supplied to the Russian army, and in world war II the further developed Big Four did excellent service in the British army.
The 82 x 120 mm engine was very reliable and had lots of bottom power.
The compression ratio was a relatively low 4.8 : 1.
The model name originated from the “ 4 HP” designation it got in its early years.
New for 1927 were more robust front forks and larger diameter brakes.
The Big 4 was available as Model 1 with 3 speed gear and as Model 14 with 4 speed gear and fully enclosed rear chain.
This machine has been restored a number of years ago and comes complete with acetylene lighting system and Lucas bulb horn.
The spark is generated by a C.A.V. magneto.