1948 Norton ES 2 500 cc OHV frame C 415934 engine C 413573
The ES 2 was Norton’s second OHV model; the Model 18 was brought out in 1923 and for the 1928 season a new model OHV was marketed, based on the successful new OHC racer that would be marketed as the CS 1.
The new OHV was designated ES 2; it was basically the pushrod Model 18 engine , but with its pushrod return springs enclosed, hence Enclosed Springs 2.
We may wonder if there also was a ES 1 design; possibly the ES 1 model name would resemble the CS 1 too much and therefore the ES 2 was more discriminate.
Just guessing, of course!
The design was step –by-step improved through the thirties: it got a four speed foot-change gearbox, rubber-mounted handlebars, fully enclosed and positively-lubricated valve gear and new cams with flat followers for quieter running.
For 1939 plunger rear suspension was available as an optional extra. After WW2 the model got the new Roadholder telescopic fork and plunger rear suspension as standard.
In 1953 ( the year of the AMC merger) swinging arm rear suspension was available and the ES 2 got a featherbed frame in 1959.
In 1963 the last ES 2 left the production line – but this was at Plumstead, not Bracebridge Street….