Manufacturer | Norton |
---|---|
Production | 1949-1955 |
Assembly | Bracebridge Street, Birmingham |
Successor | Norton Model 77 Dominator |
Engine | 497 cc (30.3 cu in) air-cooled OHV vertical twin |
Bore / stroke | 66 mm × 72.6 mm (2.60 in × 2.86 in) |
Compression ratio | 6.7:1 |
Top speed | 95 mph (153 km/h) |
Power | 29 bhp (22 kW) @ 6,000 rpm |
Ignition type | Lucas magneto |
Transmission | Wet clutch, 4-speed, chain drive |
Suspension | Front: telescopic forks Rear: plunger (1949-53), swinging arm (1953-55) |
Brakes | 7 in (180 mm) drum front & rear |
Tyres | 3.00x21 front, 3.50x19 rear (1949-53) 3.25x19 front, 3.50x19 rear (1953-55) |
Wheelbase | 54.5 in (1,380 mm) |
Dimensions | L: 84.5 in (2,150 mm) W: 28 in (710 mm) |
Seat height | 31 in (790 mm) |
Weight | 413 lb (187 kg) (dry) |
Fuel capacity | 3.75 imp gal (17.0 L; 4.50 US gal) |
Footnotes /references [1] [2] [3] [4] [5] |
The Norton Model 7 Dominator was a 500 cc vertical twin motorcycle manufactured by the Norton Motorcycle Company from 1949 to 1955. It was the first of Norton's Dominator range of motorcycles. The engine was designed by Bert Hopwood and was a departure from Norton's previous practice of producing single-cylinder machines. The Model 7 was used in Japan as a police motorcycle. [6]
In post-WW2 Britain, motorcycle manufacturers were getting back to production of civilian machines following the production of military machines. The British Government had launched an 'Export or Die' campaign to aid the economic recovery from war. Triumph's 1937 Speed twin had been well received and other manufacturers started to design their own 500 cc twins. [4] [5] [7] [8]
Having worked under designers Val Page at Ariel and Edward Turner at Triumph, where he assisted with the design of the Triumph Speed Twin, Hopwood was poached by Norton to design a new twin engine. [9]
The new Model 7 Dominator, using Hopwood's engine in adapted Norton ES2 cycle parts, was launched at the November 1948 Earls Court Motorcycle Show. [4] [10]
The engine had a 360-degree built up crankshaft with central flywheels. This arrangement meant that a central main bearing could not be fitted. The outer main bearings were of ball bearing on the timing side and roller bearings on the drive side. Alloy conrods were split at the big end and used a bush for the big end bearing. (The crankshaft and conrods had been tested in an earlier Norton Twin that had been designed by J.E. Moore but did not going into production). The camshaft was fitted in front of the engine, driven by a chain off a half-speed pinion. For ignition, a Lucas magneto was fitted at the rear of the engine, and to supply power for the lights a dynamo was fitted at the front of the engine. Both were driven by chains. [2] [3] [4] [5]
The cylinder block was in cast iron and had an integral push rod tube. Cast iron was also used for the cylinder head, which had cast-in rocker boxes to eliminate potential oil leaks between head and rocker boxes. A shallow combustion chamber, combined with low included-angle valve configuration and flat top pistons gave a good swirl effect. The head had widely splayed exhaust ports to aid cooling. A single Amal carburettor fed fuel to the engine through an alloy manifold. On the show model, the manifold was part of the head casting. [2] [3] [4] [5]
The engine used a traditional long stroke with a bore and stroke of 66 mm (2.6 in) x 72.6 mm (2.86 in) and produced 29 bhp (22 kW) at 6,000 rpm. [2] [3] [4] [5]
An alloy version of the cylinder head was available to special order in 1952. Previously this had been developed for use on Norton Competition machines from 1950 on. Notably those Norton Twins used in the ISDT Competition of 1950.
Primary drive was by chain to a wet clutch and was enclosed in a pressed steel chaincase. To fit in the ES2 frame, a new 4 speed "lay-down" gearbox was fitted. Final drive was by chain. [4] [7] [11]
The Model 7 used the cycle parts of the single cylinder ES2, which used Norton's 'garden gate' plunger frame and long 'road holder' forks. Brakes were single width 7 in (180 mm) drum brakes front and rear. Although the Model 7 engine had been fitted into the swinging arm 'featherbed frame' to produce the lighter and better handling Model 88 in 1952, production of the Model 7 continued as the featherbed was thought to be unsuitable for sidecar use. [12]
A new rear sub-frame was designed by development engineer Bob Collier in 1953, giving the bike swinging arm rear suspension [13] and a larger 8 in (200 mm) front brake was fitted in 1954. [12]
Norton' factory records show that the initial production of the Model 7 was for Australia. [9] At the August 1950 Brisbane show, Australia's annual motorcycle show, a rigid framed version of the Model 7 was shown on the stand of Andersons Agencies, an Australian Norton dealer. [14] (Bob Collier of Norton's experimental department had produced a prototype rigid framed model for the 1950 racing season.) [9] The rigid model was promoted as being 2 in (51 mm) lower and 10 lb (4.5 kg) lighter than the plunger version. The rigid model was known variously as the 'Model 77', 'Model 77 Sport Twin', 'Dominator Rigid' and the 'Dominator Rigid Sport'. Factory records show that 237 rigid machines were sent to Australia between April 1950 and February 1952. [14]
The Norton Motorcycle Company is a brand of motorcycles headquartered in Solihull, West Midlands,, England. For some years around 1990, the rights to use the name on motorcycles were owned by North American financiers.
The Norton Commando is a British Norton-Villiers motorcycle with an OHV pre-unit parallel-twin engine, produced by the Norton Motorcycle company from 1967 until 1977. Initially having a nominal 750 cc displacement, actually 745 cc (45.5 cu in), in 1973 it became an 850 cc, actually 828 cc (50.5 cu in). It had a hemi-type head, similar to all OHV Norton engines since the early 1920s.
The AJS 500cc Model 18 and AJS Model 18S are 500 cc British motorcycles almost identical to the Matchless G80 and both were produced in the same Associated Motor Cycles (AMC) London factory from 1945 to 1966. These bikes represent the end of the era of big British singles, as when AMC merged with Norton production concentrated on twins.
The BSA Golden Flash, commonly referred to as the Gold Flash, was a 646 cc (39.4 cu in) air-cooled parallel twin motorcycle designed by Bert Hopwood and produced by Birmingham Small Arms Company (BSA) at Small Heath, Birmingham. The Golden Flash was the first model in the BSA A10 series. It was available in black and chrome; but it was the distinctive golden paint scheme that gave The Golden Flash its name. Production continued until 1963, when it was superseded by the BSA A65 Star.
The Norton ES2 is a Norton motorcycle produced from 1927 until 1964. From 1965, a different machine was produced for a short time by parent manufacturer AMC, based on a Matchless but badged as Norton ES2 Mk2.
The Norton Manx or Manx Norton is a British racing motorcycle that was made from 1947 to 1962 by Norton Motors Ltd. Norton had contested every Isle of Man TT race from the inaugural 1907 event through into the 1970s, a feat unrivalled by any other manufacturer, and the development and honing of the Manx racing motorcycle was another step in this racing achievement.
The Dominator is a twin cylinder motorcycle developed by Norton to compete against the Triumph Speed Twin. The original Dominator was designed in 1947 and 1948 by Bert Hopwood, who had been on the Speed Twin design team at Triumph. Available for sale from mid 1949, this design set the pattern for Norton twins for the next 30 years.
The Norton International or Cammy Norton is a Norton Motors Ltd overhead cam (OHC) motorcycle built between 1931 and 1957.
The featherbed frame was a motorcycle frame invented by the McCandless brothers and offered to the British Norton motorcycle company to improve the performance of their racing motorcycles in 1950. It was considered revolutionary at the time, and the best handling frame that a racer could have. Later adopted for Norton production motorcycles, it was also widely used by builders of custom hybrids such as the Triton, becoming legendary and remaining influential to this day.
The BSA A7 was a 500cc motorcycle model range made by Birmingham Small Arms Company (BSA) at its factory in Armoury Road, Small Heath, Birmingham. The range was launched in 1946 using a 495 cc (30.2 cu in) long stroke engine. An improved 497 cc (30.3 cu in) version based on the BSA A10 engine was launched in 1950. The various A7 models continued in production with minor modifications until 1961/2 when they were superseded by the unit-construction A50 model.
The BSA B50 was a single-cylinder 499 cc (30.5 cu in) ohv motorcycle, produced by BSA at their factory in Small Heath, Birmingham. The last of the big capacity unit-construction singles from the Birmingham Small Arms company, it had an alloy engine with a bore of 84 mm (3.3 in) and a stroke of 90 mm (3.5 in). As well as the road version, special models were produced for off-road competition use.
The BSA A10 series was a range of 646 cc (39.4 cu in) air-cooled parallel twin motorcycles designed by Bert Hopwood and produced by Birmingham Small Arms Company at Small Heath, Birmingham from 1950 to 1963. The series was succeeded by the A65 unit construction models.
The Norton Commando Production Racer was a hand built production racer produced by Norton-Villiers from 1970 - 1972. It was based on the road-going Norton Commando, and although fitted with lights it was never intended as a road bike. The model was commonly known as the Yellow Peril.
The Norton Nomad was a dual-sport motorcycle produced for the American market between 1958 and 1960 by the British manufacturer Norton. The machine was available with either 500 or 600 cc twin cylinder engines and was produced in small quantities, around 50 of the smaller engine and around 300 600 cc machines. The first Nomad imported to the US finished 8th in California's Big Bear Run. 822 competitors has started the race. The 600 Nomad was designated with model number N15 (1958), P15 (1959) and R15 (1960). The 500 was designated N16/P16/R16. The Nomad was the first in a line of on/off road machines which culminated in the Ranger.
The 1st Norton Model 77 Dominator was a 500 cc all iron vertical twin rigid framed Norton motorcycle manufactured by Norton Motors Ltd from 1950 to 1952. All 237 examples were exported to Australia. Very little publicity surrounded this model - so much so that it was denied that they existed for some decades. It is possible that they were intended to be sidecar haulers, but the stock Model 7 - with the identical all iron engine- was equipped with sidecar mounting points, so this aspect is still a matter of discussion.
The Norton Model 88 Dominator, also originally known as the Dominator De Luxe was a 500 cc vertical twin motorcycle manufactured by the British Norton Motorcycle Company from 1952 to 1966. It was the first of Norton's motorcycles to use the featherbed frame, which established Norton's reputation of producing fine handling machines. The 88 used the Bert Hopwood designed engine that was first fitted to the Model 7 and was initially for export only. It became available on the home market in 1953. Norton were a small manufacturer at the time and without the economies of scale the model was expensive compared to other manufacturer's equivalent machines. The 88 retailed for 20% more than the contemporary Triumph Speed Twin and was dearer than the 650 cc Triumph Thunderbird.
The Norton Model 99 Dominator was a 600 cc vertical twin motorcycle manufactured by the British Norton Motorcycle Company at their Bracebridge St, Birmingham factory from 1956 to 1962. The 99 was based on the 500 cc Model 88 Dominator with an enlarged engine. The model was superseded by the 650SS.
The Norton Manxman was a 650 cc vertical twin motorcycle manufactured by the British Norton Motorcycle Company at their Bracebridge St, Birmingham factory for export. The engine was an enlargement of the 600 cc engine used in the Model 99 Dominator. The Manxman was first shown at the November 1960 Earls Court Motorcycle Show and listed by the American importer, Berliner, in their catalogue from 1961 to October 1962 Berliner had asked for the model to be named Manxman although the twin had never been raced at the Isle of Man.
The Norton 650 Dominator was a 650 cc vertical twin motorcycle manufactured by the British Norton Motorcycle Company from 1962 to 1967. Initially production was at Norton's Bracebridge St, Birmingham factory, but following the factory's closure in 1963, production was transferred to parent company AMC's works in Plumstead, London. Initially produced in single and twin carburettor versions, the single carb version was soon discontinued. The twin carb version, the 650SS, was described as the 'Best of the Dominators'.
The Norton Mercury was a 646 cc (39.4 cu in) air-cooled OHV parallel twin motorcycle made by Norton-Villiers from 1968 to 1970. It was the last Norton model to use the 'featherbed' frame. Following the collapse of AMC and the subsequent formation of Norton Villiers, the company's focus had been on the new Norton Commando. There was a large inventory of parts from previous models that would not be used on the Commando, and to use up this stock the Mercury was conceived. The Mercury was introduced in October 1968 and around 750 machines were produced, most of the production going to the US. The model was also used by the Nigerian Police.