Norton 1935 Model ES 2 490 cc OHV single frame # 3151 engine # 49648
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 probably was more discriminate.
For 1935 there were OHV models in capacities of 348, 490 and 596 cc.
Most popular was the 490 cc class, with bore and stroke dimensions just as they were in 1911, 79x100mm.
In this class there was a choice between the Model 18, the Model 20 ( with two port head) and the ES 2, which had a closed frame.
With these models the pushrods and overhead rocker gear are enclosed, but the valve springs are nice out in the open.
This ES 2 is an older restoration.