1954 Norton 350cc
The factory racing machines for the 1954 season
were tried out at Floreffe where Ray Amm gained
second place in both 350 and 500 classes. Whilst
the bikes looked more or less as before, the
engines were considerably altered. In the search
for higher rpm to compete with the 4 cylinder
Italians, the Norton engines had a higger bore
and shorter stroke than previously and so were
able to employ shorter con-rods. To minimise
crankcase size and to reduce oil drag, the internal
flywheels were replaced by a single external
flywheel mounted behind the engine sprocket.
Transmission changes included the fitting of
a rubber element engine shaft shock absorber,
the adoption of a 5 speed gearbox with direct
operating gear pedal and a 5 plate clutch.
This was to be the last year of the true works
machines, Norton's future policy being that
the works riders should use standard Manx Nortons
with various minor details on test for inclusion
in the following year's production models.
If the trus 1955 works machines had been revealed,
they would have had horizontally mounted outside
flywheel engines with an integral 5 speed gearbox.
This would have been designated the 'F' type
and on test gave as much power at the rear wheel
as the 1954 engines gave at the crankshaft.
However, special racing machines had become
too expensive and the machine in the picture
is an example of the last of Norton's Works