Four-stroke, twin-cylinder, two
valves per cylinder operated by pushrods
Capacity
497 cc / 30.3 cu in
Bore x Stroke
66 x 73 mm
Compression Ratio
8.5:1
Cooling System
Air cooled
Induction
2 x Amal Monobloc 11/16 in bore carburettors
Starting
Kick
Max Power
26.8 kW / 36 hp @ 7000 rpm
Transmission
4 Speed
Final Drive
Chain
Frame
Full duplex cradle 'Featherbed' type
Front Suspension
Telescopic forks with coil springs
Rear Suspension
Swinging arm with adjustable, three position
hydraulically damped Girling units
Front Brakes
Drum, Ø203 mm / Ø8 in
Rear Brakes
Drum, Ø178 mm / Ø7 in
Wet-Weight
185 kg / 408lb
Top Speed
177 km/h / 110 mph
One of the most successful roadsters available during the
1950s and early 1960s was the Norton Dominator. It caused a sensation when
revealed along with the unusual Velocette at the Earls Court Show of 1948. Of
497cc the Dominator was designed by the much respected Bert Hopwood who was
formerly associated with the BSA and Ariel concerns. His latest creation was to
set the Norton design trend for many years to come. In fact, even the last model
produced by the Norton company, the 850 Commando, bears a close resemblance to
the Dominator.
The engine employed was of the classic vertical twin design
with push-rod operated overhead valves. Having a bore and stroke of 66 x 73 mm
and a compression ratio of 8.5:1, the Dominator engine was tireless and a
cruising speed in the high eighties could be maintained all day long.
In 1953 the original plunger type rear suspension was replaced
by a more efficient swinging-arm arrangement and shortly afterwards the frame
was changed to the famous 'Featherbed'—a legend in itself. These improvements
now gave the Dominator excellent road manners which appealed to the
sports-minded enthusiast, who now could experience the race-bred qualities that
had previously been confined to the track.
The 1961 'sports special' model was typical of, series,
despite various modifications over the standard version. Most noticeable was the
absence of silencer on the left-hand side. Instead, twin pipes were utilized
and this obviously aided ground clearance when enthusiastic riding was called
for In fact, ground clearance was so good that only tyre adhesion determined the
angle of lean that was available.
Handling was also second to none, and on long twisting country
roads the Dominator was a joy to ride. With positive steering and taut handling it
gave the rider an unsurpassed degree of confidence. Obviously, the 'Featherbed'
frame was partly responsible but the suspension was also of a top standard. Roadholder front forks were used and" these were complemented at the rear by
adjustable hydraulically damped Girling units.
On the sports version the motor produced 36 bhp at 7000 rpm, a
good 6 bhp over the standard unit. This was mainly due to the twin Amal Monoblock
carburetors being over bored and used in conjunction with bigger inlet valves
and ports. Also, special camshaft was fitted and consequently the crankshaft was
slightly strengthened in order t take the extra output obtained.
Generally, the Dominator had a very good temperament. If
starting followed the customary drill then no difficulty was found when starting
up a cold motor. After a few kicks the engine would burst into life and the bike
would soon be ready to pull away without argument or hesitation. In town the
Dominator was docile and pleasant to use, but once on the open road the bike
would change into a beast that quickly swallowed up the miles. Into top and the
power would begin to surge once it got to 50mph. Brisk acceleration would then
continue right past the magic 'ton' until a top speed of around 110 mph was
reached. Vibration was always present but it never became unbearable or excessive
even when the motor was red-lined through the gears. Even a 7000 rpm in each gear
the motor never felt strained and once the next cog was chosen, the Dominator would
surge on until all four gears had been used to the full. All changes needed
positive use of the clutch, but generally the gearbox was faultless an never
caused concern.
The bike also excelled in braking. Here, each unit employed
was of the drum type with an eight inch at the front and a seven inch at the
rear. These could always be depended on to give surefooted stopping whenever
needed, and remarkably brake fade never occurred, even when high speed
retardation became necessary. In the wet the units remained fully watertight and
only tyre adhesion was responsible for the longer stopping distances produced.
In the dry, however, a distance of approximately 27 feet could be obtained when
braking from 30mph.
Despite some niggling faults the bike was nevertheless an
excellent sports machine. It cried out to be ridden hard and as a connoisseur's
mount the Dominator performed admirably—a true classic.
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