Introduced at the 1927 Olympia Show the Norton ES2 enjoyed a production run lasting over 30 years.
It featured a full-cradle frame (as did the OHC CS1) and the vertical single-cylinder engine shared the same 79mm x 100mm engine dimensions first used by James Lansdowne Norton as early as 1911. On the ES2, the magneto was moved behind the cylinder.
The ES2 designation was formed thus: E for extra cost, S for sports and 2 for the second version of the 79mm x 100mm long-stroke engine. Another popular explanation for ES is "enclosed springs", but that seems unlikely as this did not occur until some years after its introduction.[1]
The machine proved immensely successful in no small part due to its reliability and ease of maintenance, aided of course by their dominance in competition which put the Norton name on everyone's lips.
It was fitted with a saddle tank (as was the rest of the range by 1929) and in 1931 the magneto drive was delivered via the inlet camshaft involving a redesign of the right side crankcase. This modification was made to most other models in the 1931 range.
1934 saw the addition of a second main bearing to the drive side along with oil delivery to the valve guides via pipes. Valve gear was enclosed in 1938, and for 1939 there was optional plunger rear suspension (developed on their racing machines) and International fuel tank.
The war years saw all OHV machines dropped in favour of SV engines.
1947 saw the introduction of hydraulically damped telescopic front forks, along with rear plunger suspension as standard. The following year saw many upgrades to the engine internals, in 1950 a new gearbox was fitted, 51 saw a larger petrol tank and in 1952 swingarm rear suspension appeared, with Girling shock absorbers.
The following years saw many more enhancements - 8 inch front brakes, new cylinder head, new electrics with coil ignition and in 1959 a Wideline Featherbed frame followed by the McCandless Slimline in 1961.
Production ceased in 1963.
1939 ES2 Specifications
Engine:
Norton single port, push rod operated overhead valves; 79 mm. bore, 100 mm. stroke 490 c.c. Compression ratio 6.5 to 1; all valve gear totally enclosed and positively lubricated; coil valve springs: dry-sump lubrication: Amal carburetter; magneto ignition.
Transmission:
Renolds chains; primary ½ in. by .305 in; rear 5/8" in by .25in.; the primary chain running in oil bath; four-speed gearbox giving ratios of 4.64, 5.61, 8.2 and 13.76 to 1; multiple clutch with Ferodo inserts. Vane-type shock absorbers on clutch centre.
Frame:
Cradle type with special Norton front forks, incorporating patent rebound springs. Rear wheel sprung on plunger system.
Wheels:
Chromium plate and painted rims fitted with 25-in. by 3.25-in. Dunlop tyres front and rear; 7-in. by 1¼-in. brakes.
Tank: 2¾-gallon petrol tank; separate oil tank under saddle; capacity 5½ pınts.
Dimensions : Saddle height, 27½ ins.; wheelbase, 54¾ ins. overall length, 84¾ ins.; overall width, 30 ins.; ground clearance, 4¼ ins.
Price: £81 10s.
Extras: Speedometer, £2 10s.; pillion rests, 8s. 6d.; pillion seat, 10s.
Makers: Norton Motors, Ltd., Bracebridge Street, Birmingham.
Tax: £2 5s. per annum.
490cc OHV 1964
This machine was a rebadged Matchless G80 or AJS Model 18 marketed by AMC with some Norton parts fitted including the wheel hubs, brakes and front suspension.
Notes 1. Yesterdays NL writes: "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."
Norton Models 1936-1939
