Norton Model 99 Dominator

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Norton Model 99 Dominator
Norton Model 99 Dominator Deluxe 600cc (1956).jpg
1956 99 Dominator
Manufacturer Norton
Production1956-1962
AssemblyBracebridge St, Birmingham
Successor Norton 650SS
Engine 597 cc (36.4 cu in) air-cooled OHV vertical twin
Bore / stroke 68 mm (2.7 in) x 82 mm (3.2 in)
Power 31 bhp (23 kW) @ 5,750 rpm (88)
44 bhp (33 kW) @ 6,750 rpm (88SS)
Transmission Wet clutch, 4-speed, chain drive
Frame type Featherbed duplex cradle
Suspension Front: telescopic forks
Rear: swinging arm
Brakes drum front & rear
Wheelbase 55.5 in (1,410 mm)
Weight390 lb (180 kg) (dry)
410 lb (190 kg) (wet)
Footnotes /references
[1] [2] [3]

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 The model was superseded by the 650SS.

Contents

Background

Norton had first started exporting to the US in 1949. The Americans were impressed with Norton's racing successes but wanted a twin that was capable of the 'ton' 100 mph (160 km/h). The 88 Dominator was only capable of 90 mph (140 km/h) and was no match for the 650 Triumph Thunderbird and BSA Golden Flash. [2] Norton needed more power for the American market. [4]

Bert Hopwood had designed the 500 cc vertical twin that powered the 88. [2] Hopwood had left Norton and moved to BSA where he redesigned Val Page's earlier twin to produce the 650 cc Golden Flash. [5] Hopwood was back at Norton in 1955 and enlarged his twin engine to 600 cc to produce more power. [2]

Technical details

Engine and transmission

The 597 cc engine was enlarged from the 88's 500 cc engine by increasing the bore and stroke from 66 mm (2.6 in) x 72.6 mm (2.86 in) to 68 mm (2.7 in) x 82 mm (3.2 in). [3] The pre-unit 360° pushrod vertical twin used cast iron cylinders and an alloy cylinder head with a 7.6:1 compression ratio. Fuel was fed by a single Amal Monobloc carburettor except on the 99SS where twin carbs were fitted. [2]

Ignition was from a Lucas magneto and the power for the lights was from a dynamo. In 1958 this was changed to coil ignition and a crankshaft mounted alternator. [2] The model reverted to a magnito in 1962. [6]

Primary drive was by chain to a multiplate wet clutch and was enclosed in a pressed steel chaincase. The gearbox had 4 speeds. [2] For the 1957 model the gearbox was changed to the AMC gearbox used on AJS and Matchless twins. [7]

Cycle parts

Cycle parts were shared with the 88. The frame was the featherbed and forks were short Roadholders. Full width alloy hubs were fitted with drum brakes, 8 in (200 mm) at the front and 7 in (180 mm) rear. A 7 in (180 mm) headlight was fitted with the speedo, ammeter and switch mounted in its shell. [2] [8]

The featherbed frame was modified in 1960 by moving the top tubes closer together. The updated frame came to be known as the 'slimline' and the previous version as the 'wideline'. [9] [10]

Model variants

99

1959 Dominator 99 'Smooth-Look' Norton Dominator 99 600cc (1959) (15531064552).jpg
1959 Dominator 99 'Smooth-Look'

The Model 99 was introduced in 1956. Norton updated their range, including the 99, to their new 'Smooth-Look'. Changes included new headlight shells, detachable embellishment panels on the petrol tank, new silencers and front hub. [11] A redesigned cylinder head was also fitted. [3] The Dominator name was revived in 1959 and the model was called the Model 99 Dominator. [12] With the introduction of the 'Bodystyled' Deluxe model, the existing bike became the 88 Standard Dominator. [13] The model was discontinued in 1962 following the introduction of the 650 cc Dominators. [14]

99 De Luxe

Norton had first introduced semi-enclosed bodywork in 1958 on the 250 cc Norton Jubilee. [14] The 'Bodystyled' semi-enclosed bodywork was offered as an option on the Dominators in 1960, the De Luxe models. [13] [14] Intended as a tourer, the semi-enclosed bodywork was claimed to keep the rider cleaner and the bodywork was easier to clean than a bare design. A fairing was offered as an optional extra. Many of these models later had the bodywork stripped off to convert the bike to a cafe racer. The model was discontinued in 1962. [14]

99 Sports Special

The 99 Sports Special Dominator (99SS) was introduced in 1961 as a higher performance version of the 99. The model had the option of twin Amal Monobloc carburettors, and came with polished inlet ports and a hotter camshaft that had previously been fitted to the Manxman. A siamesed exhaust was fitted, or the option of a dual system and the option of chrome mudguards. Motor Cycle magazine obtained a top speed of 108 mph (174 km/h) during a test of the 99SS. The model was dropped after only a year when the 650SS was introduced in 1962. [15] [16]

Related Research Articles

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BSA Golden Flash

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Norton Manx

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Norton Dominator

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.

Norton Atlas Motorcycle powered by straight-twin engines

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Featherbed frame Motorcycle frame

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.

BSA A7

The BSA A7 was a 500cc motorcycle model range made by Birmingham Small Arms Company (BSA) at their 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.

Norton Jubilee

The Jubilee is a Norton motorcycle made from 1958 to 1966. Named to commemorate Norton's Diamond Jubilee, the 249 cc Jubilee was a break with Norton tradition designed in response to UK legislation introduced in 1960 limiting learner riders to motorcycles of under 250 cc. It had the smallest engine ever made by Norton, and was the first Norton with a unit construction engine and gearbox.

BSA unit twins

The BSA unit twins were a range of unit construction twin-cylinder motorcycles made by the Birmingham Small Arms Company (BSA) and aimed at the US market. A range of 500 cc (31 cu in), 650 cc (40 cu in) and 750 cc (46 cu in) twins were produced between 1962 and 1972, but they were really developments of the older pre-unit A7/A10 model range with less weight. The engines had a reputation for vibration, but acceleration was good for the time, to a top speed of 100 miles per hour (160 km/h).

BSA A10 series Motorcycle

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Norton Model 7 Dominator

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.

The Norton Model 77 Dominator was a 600 cc vertical twin motorcycle manufactured by the Norton Motorcycle Company from 1956 to 1958. It was based on the Model 7 that it superseded, and was primarily intended for sidecar use. Norton modified the featherbed frame of the 88 and 99 models in 1957 to be suitable for sidecar use making the Model 77 superfluous and the model was dropped in 1958.

Norton Model 88 Dominator

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 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.

Norton 650 Dominator British motorcycle produced from 1962 to 1967

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 were soon discontinued. The twin carb version, the 650SS, was described as the 'Best of the Dominators'.

Norton Mercury

The Norton Manxman 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.

References

  1. ↑ Reynolds 1990, p. 99.
  2. 1 2 3 4 5 6 7 8 Salvadori 2019.
  3. 1 2 3 "Norton Dominator 99". RealClassic. 11 January 2017. Retrieved 27 June 2021.
  4. ↑ "Norton Dominator". Classic-British-Motorcycles.com. Retrieved 27 June 2021.
  5. ↑ Kemp 2000, pp. 120–121.
  6. ↑ Hewitt 2018.
  7. ↑ "The Norton Commando Gearbox". www.preservationcycle.com. Retrieved 29 June 2021.
  8. ↑ American Motorcyclist December 1955, p. 2.
  9. ↑ Sharkey 2021.
  10. ↑ Reynolds 1990, pp. 97–99.
  11. ↑ "1957 Norton Brochure" (PDF). Retrieved 29 June 2021– via www.classicbike.biz.
  12. ↑ "1959 Norton Brochure" (PDF). Retrieved 29 June 2021– via www.classicbike.biz.
  13. 1 2 "1960 Norton Brochure" (PDF). Retrieved 29 June 2021– via www.classicbike.biz.
  14. 1 2 3 4 Clayton 2012.
  15. ↑ "Road Test: Norton Dominator 99SS - The Classic Motorcycle". Classic Bike Hub UK. 15 March 2013. Retrieved 29 June 2021.
  16. ↑ "1961 Norton 600cc Dominator 99SS Frame no. 97413 Engine no. 97413". Bonhams. Retrieved 29 June 2021.

Bibliography

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