Norton Model 88 Dominator
The Norton Model 88 Dominator, also originally known as the Dominator De Luxe[4] 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.[5] 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.[1] 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.[6]
_(15776399275).jpg.webp) 1957 Norton Dominator 88 | |
| Manufacturer | Norton |
|---|---|
| Production | 1952-1966 |
| Assembly | Bracebridge St, Birmingham (1952-62) Plumstead, London (1962-66) |
| Predecessor | Norton Model 7 Dominator |
| Engine | 497 cc (30.3 cu in) air-cooled OHV vertical twin |
| Bore / stroke | 66 mm (2.6 in) x 72.6 mm (2.86 in) |
| Top speed | 95 mph (153 km/h) |
| Power | 29 bhp (22 kW) @ 6,000 rpm 36 bhp (27 kW) @ 7,000 rpm (88SS) |
| Ignition type | Lucas magneto |
| Transmission | Wet clutch, 4-speed, chain drive |
| Frame type | Featherbed duplex cradle |
| Suspension | Front: telescopic forks Rear: swinging arm |
| Brakes | drum front & rear |
| Tyres | 3.00x19 front, 3.50x19 rear |
| Wheelbase | 55.5 in (1,410 mm) |
| Dimensions | L: 84 in (2,100 mm) W: 26 in (660 mm) |
| Seat height | 31 in (790 mm) |
| Weight | 380 lb (170 kg) (dry) |
| Fuel capacity | 3.5 imp gal (16 L; 4.2 US gal) |
| Footnotes / references [1][2][3] | |
Technical details
Engine and transmission
The 497 cc Bert Hopwood designed engine from the Model 7 was used in the 88. The pre-unit 360° pushrod vertical twin used cast iron cylinders and head. Ignition was by a magneto mounted behind the engine and power for the lights was supplied by a dynamo.[7] Later models used an alternator and coil ignition.[8]
An alloy cylinder head was introduced in 1955[2] and various improvements were make to the engine during the model's production run.
Primary drive was by chain to a multiplate wet clutch[9] and was enclosed in a pressed steel chaincase. Oil leaks from the chaincase were a common problem.[7][10] The gearbox had 4 speeds.[8]
Cycle parts
Norton had commissioned Belfast racer and engineer Rex McCandless to build a new frame for their Manx racers. The McCandless frame was first used in 1950 and brought many victories for the Norton team and praise from the riders.[11] The landmark design influenced motorcycle chassis design for many years.[12] The 88 used the featherbed frame to provide a sportier road bike, although the road going versions of the frame were made from mild steel tubing rather than the Reynolds 531 tube of the racers. Early frame could distort if bumped into a curb which was resolved by adding a reinforcing gusset.[7] The frame was 30 lb (14 kg) than the ES2 type frame of the Model 7.[13]
Front suspension was short Roadholder forks and rear swinging arm pivoting on Silentbloc bushes.[14] Brakes were 7 in (180 mm) single width drums front and rear[7] although full-width hubs were later fitted.[8]
The first models were finished in Norton's trademark polychromatic grey colour scheme.[10] In 1959 metalescent blue, red and black/silver finishes were offered as options.[15] Two-tone finishes were introduced with the Standard model being offered in red/dove grey, black/dove grey and two-tone grey. The De Luxe was available in red/dove grey, blue/dove grey and green/dove grey.[16] No colour options were offered in 1961, the Standard being finished in two-tone grey and the De Luxe in blue/dove grey.[17] In 1963 the Standard model was offered in green/off-white and the SS in black with a silver tank.[18]
Model naming and variants
The Model 7 Dominator had been introduced in 1949. When the featherbed framed model 88 was introduced it was designated the 'Dominator De Luxe' to differentiate it from the Model 7.[6] In 1956 the 'Dominator' name was dropped and the bike was designated simply as the 'Model 88'.[19][20]
The Dominator name returned for 1959 with the model being known as the 88 Dominator.[15] In 1960 a new 'body styled' variant was introduced with enclosed rear bodywork. This was known as the Dominator De Luxe and the existing model became the Dominator Standard.[16]
A sports version, the 88 Dominator Sports Special was introduced in 1961.[21] The De Luxe model was discontinued in 1962, the Standard in 1963 and the SS model continued production until October 1966.[8]
| Model | |||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Standard | 88 Dominator De Luxe | 88 | 88 Dominator | 88 Dominator Standard | |||||||||||
| Enclosed rear bodywork | 88 Dominator De Luxe | ||||||||||||||
| Sports | 88 Dominator Sports Special (SS) | ||||||||||||||
88 Sports Special
The Sports Special (SS) version of the 88 Dominator was introduced in 1961. Power output was increased to 36 bhp (27 kW) @ 7,000 rpm by using twin 1 1/16" (27mm) Amal Monobloc carburettors,[21] larger 1.4 in (36 mm) inlet valves,[22] the camshaft from the 650 Manxman, 8.5:1 compression ratio and a siamesed exhaust. A test conducted by Motor Cycling at the MIRA testing ground showed the machine capable of reaching the 'ton' (100 mph).[21]
In 1962 the head from the 650SS was fitted in 1962 which had larger 28.5mm inlet ports which were angled down, 40° splayed exhaust ports to improve cooling and larger fins.[22] The 88SS was produced until October 1966.[8]
Model history
An experimental featherbed framed dominator was first seen in Holland in 1951, and the 88 was officially launched at the Earls Court Motorcycle Show later in the year.[13]
The model sold well in 1952 but supplies of the frame, which was fabricated by Reynolds Tubing, limited production to around 20 machines a week.[23]
The bolt-on rear part of the frame was replaced with a welded-on sub-frame[24] and the front brake increased to 8 in (200 mm) in 1954.[7]
Full width alloy hubs were introduced for the 1956 models along with a new Lucas headlamp with the speedo, ammeter and switch located in the headlamp shell. Compression ratio was raised to 7.8:1 from 6.8:1 to take advantage of the better fuel that was now available.[19] An alloy head was also fitted in this year,[2] which was 13 lb (5.9 kg) lighter than the previous cast iron item.[22]
For the 1957 model the gearbox was changed to the AMC gearbox used on AJS and Matchless twins.[25]
An alternator and coil ignition were fitted in place of the magneto and dynamo from 1958.[26]
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'.[1][27] Compression ratio was increased to 8.1:1, gear ratios changed and bonded clutch plates fitted.[16]
A new head was introduced in 1961 on the 88SS model with larger finning and inlet valve increased from 1.3 in (33 mm) to 1.4 in (36 mm). This head was also fitted to the Standard 88 from 1962.[22]
In 1962 the 88SS was fitted with the cylinder head used on the 650SS which had larger 28.5mm inlet ports which were angled down, 40° splayed exhaust ports to improve cooling and larger fins.[22]
Racing
The Norton racing team starting developing the 88 for racing, the machines being known as Domiracers. Initially they were no match for the Manx Norton. Under Doug Hele's guidance the machine was developed to increase power to 55 bhp (41 kW) and the machines were 35 lb (16 kg) lighter than the Manx.[28]
The first outing for the racing 88s was at the 1953 Daytona 200 where a pair of machines were entered and Milt Lassiter finished third.[29]
In 1960 Dennis Greenfield and Fred Swift won the 500 cc class of the Thruxton 500 on a Domiracer. Tom Phillis came third in the 1961 Isle of Man TT Senior race and was the first rider to achieve a 100 mph lap on a pushrod bike and also it was the first 100 mph lap on a twin.[1][28]
An 88SS won the 1962 1,000 km production race at Silverstone.[30]
The factory stopped the Domiracer project in 1962 and the bikes and spares were sold to Paul Dunstall who continued their development.[1][31]
References
- Sharkey 2021.
- Reynolds 1990, p. 99.
- "1954 Norton Brochure" (PDF). Retrieved 20 June 2021 – via www.classicbike.biz.
- American Motorcycling March 1953.
- Holmes 2007, p. 140.
- "Road Test: Norton Dominator Model 88". The Classic Motorcycle. 27 August 2014. Retrieved 24 June 2021.
- "Norton Dominator". Classic-British-Motorcycles.com. Retrieved 26 June 2021.
- "1956 Norton 497cc Dominator 88 Frame no. 71331 Engine no. 71331". Bonhams. Retrieved 26 June 2021.
- "1957 Norton Dominator". Classic-British-Motorcycles.com. Retrieved 26 June 2021.
- Melling 2003.
- Walker 2006, pp. 40–49.
- Foale 2006, pp. 1–6, 1–7.
- Reynolds 1990, p. 96.
- "1955 Norton 497cc Dominator 88 Frame no. K122 62984 (see text) Engine no. 62984 K122". Bonhams. Retrieved 26 June 2021.
- "1959 Norton Brochure" (PDF). Retrieved 26 June 2021 – via www.classicbike.biz.
- "1960 Norton Brochure" (PDF). www.classicbike.biz. Retrieved 26 June 2021.
- "1961 Norton Brochure". Retrieved 26 June 2021 – via www.motobrit.com.
- "1963 Norton Brochure". Retrieved 26 June 2021 – via www.motobrit.com.
- American Motorcyclist December 1955.
- "1956 Norton Brochure". Retrieved 20 June 2021 – via www.motobrit.com.
- Motor Cycling May 1961.
- "Norton heavy twins heads". atlanticgreen.com. September 2016. Retrieved 25 June 2021.
- Reynolds 1990, pp. 96–97.
- "Norton Dominator 99". RealClassic. 11 January 2017. Retrieved 28 June 2021.
- "The Norton Commando Gearbox". www.preservationcycle.com. Retrieved 29 June 2021.
- "1958 Norton Brochure". Retrieved 26 June 2021 – via www.motobrit.com.
- Reynolds 1990, pp. 97–99.
- Cloesen 2016, p. 39.
- Walker 2006, p. 210.
- Walker 2013.
- Cloesen 2016, p. 40.
Bibliography
- Cloesen, Uli (1 September 2016). British Café Racers. Dorchester, Dorset: Veloce Publishing Ltd. ISBN 978-1-84584-896-5.
- Foale, Tony (2006). Motorcycle handling and chassis design : the art and the science (2nd ed.). Benidoleig, Spain: Tony Foale Designs. ISBN 978-84-933286-3-4.
- Holmes, Mark (2007). Ultimate motorcycles : the most exotic & exclusive bikes on earth. Edison, NJ: Chartwell Books. ISBN 978-0-7858-2284-4.
- Melling, Frank (27 September 2003). "Classic bikes: Norton Dominator". Daily Telegraph. Archived from the original on 10 November 2012. Retrieved 26 June 2021.
- Reynolds, Jim (1990). Best of British bikes. Patrick Stephens. ISBN 978-1-85260-033-4.
- Sharkey, Alex (19 March 2021). Classic Bikes: Essential Transport. Character-19.
- Walker, Mick (November 2006). The Manx Norton. Redline Books. ISBN 978-0-9544357-9-0.
- Walker, Mick (20 January 2013). British Motorcycles of the 1960s and '70s. Oxford [England]: Bloomsbury Publishing. ISBN 978-0-7478-1315-6.
- "Norton Space No.12". American Motorcycling. March 1953. p. 18 – via WALNECK'S CLASSIC CYCLE TRADER, MARCH 1990.
- "The 497 cc Norton Dominator 88SS". Motor Cycling. 11 May 1961. pp. 52–56 – via WALNECK'S CLASSIC CYCLE TRADER, DECEMBER 1995.
- "Norton "Two Group" Program For 1956". American Motorcyclist. December 1955. p. 24.
