The Norton Model 99 Dominator was a 600 cc vertical twin motorcycle manufactured by the British
Norton Motorcycle Company
The Norton Motorcycle Company (formerly Norton Motorcycles.) is a brand of motorcycles headquartered in Solihull, West Midlands, (originally based in Birmingham), England. For some years around 1990, the rights to use the name on motorcycles we ...
at their Bracebridge St,
Birmingham
Birmingham ( ) is a City status in the United Kingdom, city and metropolitan borough in the metropolitan county of West Midlands (county), West Midlands, within the wider West Midlands (region), West Midlands region, in England. It is the Lis ...
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 The model was superseded by the 650SS.
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' . The 88 Dominator was only capable of and was no match for the 650
Triumph Thunderbird
The Triumph Thunderbird is a British motorcycle that was introduced by Triumph Engineering, Triumph back in 1949 and produced in many forms until 1966. The name was used three more times for new and distinct Triumph models.
Original Triumph: 6 ...
and BSA Golden Flash. Norton needed more power for the American market.
Bert Hopwood
Herbert Hopwood (1908 – 17 October 1996) was a British motorcycle designer. He designed motorcycles for Ariel, Norton, BSA and Triumph.
Motorcycle design career
Hopwood left school at an early age to work for Ariel under designer Val Pa ...
had designed the 500 cc vertical twin that powered the 88. Hopwood had left Norton and moved to BSA where he redesigned
Val Page
Valentine Page (1891–1978) was a British motorcycle designer. He worked for leading UK marques including JAP, Ariel, Triumph, and BSA. Page was an innovator whose radical designs include the Triumph 6/1; BSA Gold Star, M20, and A7; Ari ...
's earlier twin to produce the 650 cc Golden Flash. Hopwood was back at Norton in 1955 and enlarged his twin engine to 600 cc to produce more power.
Technical details
Engine and transmission
The 597 cc engine was enlarged from the 88's 500 cc engine by increasing the bore and
stroke
Stroke is a medical condition in which poor cerebral circulation, blood flow to a part of the brain causes cell death. There are two main types of stroke: brain ischemia, ischemic, due to lack of blood flow, and intracranial hemorrhage, hemor ...
from x to x . The pre-unit 360° pushrod vertical twin used cast iron
cylinders
A cylinder () has traditionally been a three-dimensional solid, one of the most basic of curvilinear geometric shapes. In elementary geometry, it is considered a prism with a circle as its base.
A cylinder may also be defined as an infinite ...
and an alloy
cylinder head
In a piston engine, the cylinder head sits above the cylinders, forming the roof of the combustion chamber. In sidevalve engines the head is a simple plate of metal containing the spark plugs and possibly heat dissipation fins. In more modern ...
with a 7.6:1
compression ratio
The compression ratio is the ratio between the maximum and minimum volume during the compression stage of the power cycle in a piston or Wankel engine.
A fundamental specification for such engines, it can be measured in two different ways. Th ...
. Fuel was fed by a single
Amal Monobloc
AMAL was a British engineering company servicing the motorcycle and other light-engineering motor industries between 1927 and 1993carburettor
A carburetor (also spelled carburettor or carburetter)
is a device used by a gasoline internal combustion engine to control and mix air and fuel entering the engine. The primary method of adding fuel to the intake air is through the Vent ...
except on the 99SS where twin carbs were fitted.
Ignition was from a
Lucas
Lucas or LUCAS may refer to:
People
* Lucas (surname)
* Lucas (given name)
Arts and entertainment
* Luca Family Singers, or the Lucas, a 19th-century African-American singing group
* Lucas, a 1960s Swedish pop group formed by Janne Lucas Perss ...
magneto
A magneto is an electrical generator that uses permanent magnets to produce periodic pulses of alternating current. Unlike a dynamo, a magneto does not contain a commutator to produce direct current. It is categorized as a form of alternator, ...
and the power for the lights was from a
dynamo
"Dynamo Electric Machine" (end view, partly section, )
A dynamo is an electrical generator that creates direct current using a commutator. Dynamos employed electromagnets for self-starting by using residual magnetic field left in the iron cores ...
. In 1958 this was changed to coil ignition and a
crankshaft
A crankshaft is a mechanical component used in a reciprocating engine, piston engine to convert the reciprocating motion into rotational motion. The crankshaft is a rotating Shaft (mechanical engineering), shaft containing one or more crankpins, ...
mounted
alternator
An alternator (or synchronous generator) is an electrical generator that converts mechanical energy to electrical energy in the form of alternating current. For reasons of cost and simplicity, most alternators use a rotating magnetic field wit ...
. The model reverted to a magnito in 1962.
Primary drive was by chain to a multiplate
wet clutch
A clutch is a mechanical device that allows an output shaft to be disconnected from a rotating input shaft. The clutch's input shaft is typically attached to a motor, while the clutch's output shaft is connected to the mechanism that does the ...
and was enclosed in a pressed steel chaincase. The gearbox had 4 speeds. For the 1957 model the gearbox was changed to the
AMC
AMC may refer to:
Film and television
* AMC Theatres, an American movie theater chain
* AMC Networks, an American entertainment company
** AMC (TV channel)
** AMC+, streaming service
** AMC Networks International, an entertainment company
*** ...
gearbox used on
AJS
A. J. Stevens & Co. Ltd was a British automobile and motorcycle manufacturer in operation from 1909 to 1931. The company was founded by Joe Stevens in Wolverhampton, England. After the firm was sold, the name continued to be used by Matchless, ...
and
Matchless
Matchless is one of the oldest marques of British motorcycles, manufactured in Plumstead, London, between 1899 and 1966. A wide range of models were produced under the Matchless name, ranging from small two-strokes to 750 cc Four-stroke cy ...
twins.
Cycle parts
Cycle parts were shared with the 88. The frame was the
featherbed
A tick mattress, bed tick or tick is a large bag made of strong, stiff, tightly-woven material ( ticking). This is then filled to make a mattress, with material such as straw, chaff, horsehair, coarse wool or down feathers,Dictionnaire de l'ameu ...
and forks were short Roadholders. Full width alloy hubs were fitted with drum brakes, at the front and rear. A headlight was fitted with the speedo, ammeter and switch mounted in its shell.
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'.
Model variants
99
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. A redesigned cylinder head was also fitted. The Dominator name was revived in 1959 and the model was called the ''Model 99 Dominator''. With the introduction of the 'Bodystyled' Deluxe model, the existing bike became the ''88 Standard Dominator''. The model was discontinued in 1962 following the introduction of the 650 cc Dominators.
99 De Luxe
Norton had first introduced semi-enclosed bodywork in 1958 on the 250 cc Norton Jubilee. The 'Bodystyled' semi-enclosed bodywork was offered as an option on the Dominators in 1960, the ''De Luxe'' models. 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
A coffeehouse, coffee shop, or café (), is an establishment that serves various types of coffee, espresso, latte, americano and cappuccino, among other hot beverages. Many coffeehouses in West Asia offer ''shisha'' (actually called ''nargile ...
. The model was discontinued in 1962.
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
AMAL was a British engineering company servicing the motorcycle and other light-engineering motor industries between 1927 and 1993Manxman. 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 during a test of the 99SS. The model was dropped after only a year when the 650SS was introduced in 1962.