Norton ES2
Norton ES2 Background & History
The Norton ES2 was a 500cc (490cc actually) overhead valve (OHV) single that was in production from 1927 through the 1965 model year. That’s a very long run. Originally intended as a sports machine in a world that was dominated by similar big British singles, it was overtaken by faster and more powerful bikes, especially the huge crop of new British-built vertical twins. It remained popular because it was very reliable and easy to maintain, and ran well for what it was, a big British single designed in the 1920s. Norton's first pushrod single was the Model 18 in 1922, and by 1924 they were racking up a string of impressive racing successes. Displacing 500cc, it was a typically undersquare engine with a 77mm bore and a 100mm stroke. This engine's cast iron barrel and cylinder head did not include a fully-enclosed valve train, as the pushrods and valve springs were exposed. Overall it was a very good engine, strong and reliable, but when this engine was adapted to the new Norton ES2, they enclosed the valvetrain completely, which is where the model got its name. The 'ES' in 'ES2' stands for 'Enclosed Springs'. Overall it was a good choice as this engine was proven, and the tooling was already paid for.
1951 Norton ES2.
While the Model 18 had a rigid frame, only the earliest Norton ES2s had the rigid frame. In 1947, the ES2 got an Anstey-link plunger-type rear suspension, which converted to full swing arm rear suspension in 1953. Then in 1959, the frame was upgraded again to the best frame in the business, the excellent Featherbed frame, so called because of it's incredibly smooth ride.
1951 Norton ES2.
Norton ES2 Engine
Typical of the times, the Norton ES2 had a very undersquare engine design, with a bore of 79mm and a stroke of a very long 100mm. As a result, it only made 25 hp at 5,500 rpm, neither very high numbers. It was a simple, straightforward OHV (Overhead Valve) design with pushrods and rocker arms for valve actuation. The engine had proven itself in years of competition in the Model 18, and had even been stretched to 600cc for the Model 19. Early Norton ES2s had rigid frames, but in 1947 they were upgraded to Norton’s new, race-proven Garden Gate frame with a plunger-style rear suspension. In 1953, this was upgraded again to a full swing-arm rear suspension, but not the Featherbed, that would come later.
1954 Norton ES2 engine, left side.
Norton ES2 Upgrades
Then in 1959, the ES2 adopted the excellent Featherbed Frame. It was also one of the lightest, strongest, most modern, and best-handling motorcycle frames ever built. Its secret was the way it was constructed of two 20-foot lengths of Reynolds high-strength steel that were bent into two continuous loops that formed the two main frame members. And the frame was fully welded at a time when the industry was using brazed cast iron lugs to hold their frames together. It revolutionary at the time and nearly every motorcycle frame would gain from the lessons learned on the Featherbed.Also in 1959, the ES2 got a new AMC gearbox, a revised alloy cylinder head, an 8-inch front brake with full width drums, and a 60-watt alternator with coil ignition. The Norton ES2 topped out at 82 mph, but could achieve a fuel economy of 56 mph at a 60 mph constant speed. In 1961, the new Slimline Featherbed Frame was introduced to the Norton ES2 line. With a narrower backbone than the normal Featherbed, it allowed for a narrower fuel tank without sacrificing fuel capacity.
The Featherbed Frame was so good, and handled so well that racers and custom motorcycle builders dropped different engines, even different brands of engines into the Featherbed to benefit by it's incredible road manners. Triumph 650 twins were dropped in and the bikes nicknamed "Triton", for Triumph and Norton. At the time, they were called hybrids and the Featherbeds unique handling qualities meant that most hybrids were based on the Featherbed frame. Dropping a Vincent 1000cc V-twin in the Featherbed yielded a hybrid nicknamed "Norvin" for Norton and Vincent. Fun times.
In late 1964 the last Norton ES2 model was released. This one was actually a 500cc Matchless G80 single with Norton badging. There was also a 350 model, based on the Matchless G3. They only lasted two model years.
This shows the details of the plunger-style rear suspension on the Garden Gate frame of this 1954 Norton ES2.
AMC Collapses
Around this time, Norton’s owner, Associated Motor Cycles (AMC) was on the verge of financial collapse and Norton was purchased by Manganese Bronze Holdings in 1966, breaking it off from the rest of the AMC empire, which included Matchless and AJS.
This 1960 Norton ES2 shows how the Featherbed Frame looked on it. The first year for the Featherbed was 1959.
Norton ES2 Books
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