1959 Triumph Speed Twin

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Kevin Dunn's 1959 Triumph Speed Twin.
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Owner Kevin Dunn is quite proud of his meticulously restored 1959 Triumph Speed Twin, as he should be. Every detail is perfect.
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Kevin Dunn's 1959 Triumph Speed Twin.
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Kevin Dunn's 1959 Triumph Speed Twin.
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All of the engine casings on Kevin Dunn's 1959 Triumph Speed Twin have been heavily polished, and the result is one fine-looking classic twin.
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Note the bicycle-style pump at the top of the photo on Kevin Dunn's 1959 Triumph Speed Twin.
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The wide rear fender is what gave the Triumph Speed Twin its “bathtub” nickname.
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The attractive headlight nacelle on Kevin Dunn's 1959 Triumph Speed Twin.
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Kevin Dunn's 1959 Triumph Speed Twin came complete with a full set of original tools.
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Kevin Dunn's 1959 Triumph Speed Twin.

Triumph Speed Twin
Years produced:
 1959-1966
Claimed power: 27hp @ 6,500rpm
Top speed: 90mph (est.)
Engine type: 490cc OHV parallel twin
Weight: (dry) 155kg (341lb)
Price then: $710 (approx.)
Price now: $6,000-$15,000
MPG: 50-60mpg

If a bike’s impact on the industry and longevity in production are any measure of success, there are few designs that come close to the 500cc Triumph Speed Twin, the first commercially successful parallel-twin cylinder motorcycle. Almost every major motorcycle manufacturer of its time copied or emulated it, and it remained in production for 28 years.

It’s often said that there’s really nothing new in motorcycling. Most of the “new” ideas that found widespread favor starting in the 1960s — overhead camshafts, multiple valves, electric start — had all been tried before 1920, and usually abandoned because of high cost, poor fuel and underdeveloped metallurgy. The fledgling Triumph Co. actually experimented with parallel twins in the years before World War I, before abandoning its efforts in order to produce the more mundane Model H “Trusty” — the 550cc belt drive, side-valve single that served so well on the battlefield.

Edward Turner, Jack Sangster and Valentine Page
Although the Triumph Speed Twin designer, Edward Turner, started his career as a motorcycle dealer, he had a great interest in designing motorcycles. In the late 1920s, he submitted his plans for a 4-cylinder engine to Jack Sangster, owner of Ariel. Impressed, Sangster hired Turner to complete the design and put the machine into production. The result was the 500cc overhead cam 1930 Ariel Square Four. Turner became Ariel’s rising design star — a situation that did not sit well with chief designer Valentine Page.

Page left Ariel in 1932 to join Triumph, where he continued development of an idea he had hatched at Ariel: Page assembled a promising 250cc parallel twin using one of the two crankshafts from Turner’s Ariel Square Four, then took the idea one stage further, designing a 646cc OHV parallel twin. The design, known as the 6/1, incorporated many significant innovations that would find their way into later designs by other manufacturers, such as gear primary drive, a single camshaft, semi-unit construction, oil tank cast in the crankcase and more. Page’s twin proved powerful and reliable, if overbuilt and expensive to make. A limited number of machines were produced, mostly sold for sidecar duty.

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