|
The Dunstall Norton was a Norton motorcycle made by Paul Dunstall, a specialist tuner of 1960s and early 1970s twins originally using some parts from Norton's Domiracer project when the Birmingham factory was closed in 1963. In 1966 Dunstall Motorcycles became a motorcycle manufacturer in its own right, so that Dunstalls could compete in production races,〔 and set a number of world records before sales of the Dunstall Nortons declined in the 1970s consistent with the demise of the British motor cycle industry and corresponding rise in Japanese imports. Paul Dunstall had already turned his attention to modifying Japanese marques before the collapse of Norton (then part of the fated NVT) in 1974. After several more successful years he left the bike scene to concentrate his attention on property development Paul Dunstall sold the name in 1982.〔 ==Development== Paul Dunstall was a specialist tuner of Norton twins in the 1960s and early 1970s. He started modifying Nortons in 1957, at the age of 18, when he converted a Norton Dominator into a competitive racing motorcycle. As well as fitting a Norton Manx gearbox and wheels, Dunstall balanced the crankshaft and installed the Dominator engine into a Manx Norton frame. With places and two outright wins at Brands Hatch in his first season, after graduating to a higher level with places in his second season at other circuits, Dunstall retired from racing to work in his family's scooter shop and develop performance motorcycle parts〔(【引用サイトリンク】title=Dunstall Motorcycles History )〕 Initially Dunstall conceived simple 'bolt on' modifications such as 'Goldie' pattern straight-through replacement silencers which he called 'Hi-Tune'〔Motor Cycle, 29 April 1965, p.33 "''Paul Dunstall Genuine Domiracer Equipment advertisement''". Accessed 2013-08-05〕 and exhaust pipes, creating his first catalogue in 1961 and gradually growing the business.〔 Dunstall built engines for other racers and purchased parts left over from Norton's Domiracer project when the factory closed in 1963, using his know-how to further develop high performance motorcycles built to order.〔 From 1966, Dunstall's customers could choose from a standard catalogue offering a range of speed parts, race-styled accessories and complete ready-modified bikes〔Dunstall, Paul. 1966 ''Special Equipment Catalogue..for Norton, Triumph & BSA''〕 from Norton, BSA, and Triumph in capacities from 500cc upwards〔 In 1966 Dunstall Motorcycles became a motorcycle manufacturer in its own right, so that Dunstalls could compete in production races and the Auto-Cycle Union, which is the governing body for motorcycle racing in Britain, approved Dunstall Dominators as a marque for the production race in the 1967 Isle of Man TT.〔 The 1967 Dunstall Dominator 750 roadster was tested as the fastest motorcycle on the market at the time of its launch.〔() MCM Dunstall advertising ''Paul Dunstall Powerful Dominator'' Retrieved 2013-03-01〕 The early 1960s Norton factory racers were called Domiracer, and although Dunstall called his roadsters both Dominator and Domiracer at various stages and with varying engine capacities, the 750s were sometimes known as Dunstall Atlas. They were not known as 'Norton Dunstall' - this is a later corruption as all 1960s literature quote Dunstall Norton Dominator, Dunstall Dominator or Dunstall 750 Atlas.〔''Motor Cycle'', 24 June 1965, p.36 ''Dunstall advert. "A limited number of the fabulous Dunstall 750cc Atlas machines are now available for immediate delivery''". Accessed and added 2015-02-23〕〔() Grace's guide to British Industry Retrieved 2013-03-02〕 The last bikes from the featherbed-based machines in the 1969 catalogue were stated as ''Dunstall Norton Sprint'' and ''Export 750'' together with the newest bike in the range the isolastic-framed ''Dunstall Norton Commando''.〔Dunstall, Paul. 1969 ''Paul Dunstall Special Equipment'' catalogue.〕 By the late 1960s, Dunstall had sold to celebrity customers including film star Steve McQueen and Keith Emerson, of progressive rock band Emerson Lake & Palmer.〔 After the 1968 race season successes, development of the late-1940s designed parallel twin engine was nearing its zenith for the technology of the time with power outputs of 73 horsepower for the race-spec 745cc Atlas-based engine.〔 For the 1969 season, Dunstall created a new machine with a lower frontal area, the inclined engine being 'underslung' from a large-diameter steel tubing spine frame (nicknamed ''The Drainpipe'') designed by Eddie Robinson〔''Classic Bike'', August 2002, pp.58-61 ''Eddie Robinson profile. The man they call the Frame Brain'' Accessed and added 2014-11-02〕 The main frame component ran front to back with a second large-diameter vertical tube at rear of the power plant carrying the engine oil,〔 avoiding the need for the traditional separate oil tank. The filler was conventionally placed ahead of the seat nose〔(【引用サイトリンク】title=Nolan Woodbury, vintagemotorcyclesonline.com )〕 Although Dunstall's open-class racers (non production-race category) were equipped with ''lowboy'' frames〔 based on the works design which Dunstall had acquired during the Norton factory race-shop closure,〔 this re-design was based on an established concept not yet applied to the Norton twin for road racing. With no front downtube(s) hence no conventional engine mountings, the spine frame needed substantial cantilever bracing from the central-point of the frame forwards under the gearbox and engine to control the torque reaction The original 'drainpipe' configuration included aluminium dual 'pannier' fuel tanks inside the top-half fairing sides to lower the centre of gravity and improve handling but following fuel starvation problems a conventional fuel tank was fitted.〔 With discontinuation of the featherbed Atlas in 1968, Dunstall first offered his Commando-based roadsters from the 1969 ctalogue. Sales of the Dunstall Nortons declined in the 1970s and Paul Dunstall concentrated on Japanese marques, in particular forging strong links with Suzuki, eventually selling the name in 1982.〔 In their test of a 1971 Norton Dunstall 810, ''Cycle World'' measured the top speed at , with a 0 to 60 mph time of 4.7 seconds and a standing time of 11.9 seconds at .〔 This was the first bike ever in ''Cycle World''s tests with quarter mile time under 12 seconds.〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Norton Dunstall」の詳細全文を読む スポンサード リンク
|
