1969 Motorcycling History - 5-Page Vintage Motorcycle Article

Description

1969 Motorcycling History - 5-Page Vintage Motorcycle Article
Original, vintage magazine article.
Page Size: Approx. 8" x 11" (21 cm x 28 cm) each page
Condition: Good
IT WASN’T ALWAYS this good
PART ONE
Motorcycling has come a long way in a
comparatively short period of time, but it's been
a rough road in spots.
The European factories raced
with great enthusiasm in the pre-
war Grand Prix races. Much of
what was learned in road racing
was applied to the roadster
models a few years later. This is
the 1939 Benelli 250cc single
with double overhead cams that
won the 1939 250cc TT.
This 1903 British Triumph was a
typical early day motorcycle. The
Belgian made Minerva engine
featured side- valves. The
ciutchiess belt drive and the
pedal gear were standard
practice.
This 1928 Moto-Guzzi Gran
Turismo model featured one of
the earliest spring frames. The
pivoted rear fork attached to
spring boxes beneath the engine.
Note the hand gearshift and
cluttered appearance — standard
features for the 1920's.
by Richard C. Renstrom
In the history of the motorcycle there
is nothing more fascinating than a study
of design evolution down through the
years. From a crude and humble begin-
ning as an unreliable method of trans-
portation, the motorbike has evolved
into an attractive, reliable, and efficient
machine for both transportation and
sporting use.
Another captivating part of this story
is how the design and sales leadership
has passed from one country or conti-
nent to another. A review of the causes
makes an interesting study for the
serious student of the motorcycle.
These underlying reasons or causes
for motorcycle design progress may at
first appear to be strictly engineering in
nature, but a closer inspection usually
reveals that economic forces have been
a major motivating factor. Engineering
or design advancements have histori-
cally been fostered by economic needs
or forces, and this, combined with the
international aspect, has left us a legacy
of historical evolution that is without
equal in the world of design and
engineering.
This story of the motorcycle goes
back a long way to the year of 1673
when a Dutch scientist named Christian
Huygens first demonstrated the prin-
ciple of the internal combustion engine.
Huygens' engine had a piston that was
blown upwards by the explosion of
gunpowder, which was a totally imprac-
tical proposition, but it nevertheless did
demonstrate the internal combustion
principle.
The next significant invention was
several centuries later in 1860 when
French engineer J. J. E. Lenoir patented
the first successful internal combustion
engine in which the piston, for the first
half of its stroke, drew in a mixture of
gas and air which was exploded by an
electric spark. Then followed the work-
ing portion of the stroke, and after the
exhaust gas had been allowed to escape
the piston made its return journey
assisted by a heavy flywheel.
During the first half of the return
stroke the cylinder was again charged at
the opposite end, and this was followed
by the return stroke. This Lenoir engine
was not a feasible proposition either,
but it did further demonstrate the
principle of harnessed power in the LC.
engine.
The next significant development oc-
curred in 1876 in Deutz. Germany when
Dr. N A. Otto introduced the first
practical LC. engine. Dr. Otto's engine
featured the now well accepted four-
stroke principle as well as the principle
of compressing the fuel mixture to
obtain more power. This new engine
had valves which admitted a fresh fuel
charge on the downstroke of the piston,
and then the compression occurred on
the upstroke. An electrical spark ignited
the mixture at top dead center, and the
ensuing downstroke was the power
stroke. Then followed the upstroke
when the exhaust valve was opened to
expel the gas. and then the cycle was
completed all over again.
While the Otto type engine was being
developed, other early day inventors
were engaged in creating another de-
sign. Called the two-stroke type, this
engine was patented in 1881 by Eng-
land's Sir Dugald Clerk. In Sir Dugald’s
engine the valves were replaced with
ports that were uncovered by the piston
in various stages of its travel. The
upstroke had the piston compressing
the fuel mixture to ignite, while at the
same time a port was opened to allow
fresh gas to flow into the crankcase. The
downstroke was the power stroke, of
course, and it also pushed the fuel
charge from the crankcase through
transfer ports into the combustion
chamber. The exhaust port was exposed
near the bottom of the stroke, and this
principle allowed a power stroke on
every revolution of the engine.
Another factor involved was strictly
social in nature. We Americans have
always been noted as being a materia-
listic society, and nowhere has this been
more true than with motorcycles. During
the roaring twenties anyone who had
"succeeded'' drove a fine automobile,
and anyone who could afford only a
motorbike was looked upon socially as
being rather inferior. With the automo-
bile being “in" as well as financially
available to the typical American, it was
only natural that we would lose our
motorcycle design leadership to some-
one else.
The answer of who that "someone
else" would be was not long in coming,
for in England the socio-economic cir-
cumstances were ripe for assuming
world leadership. The European conti-
nent had been devastated by the war
while England had not been so badly
damaged, thus England could rapidly re-
tool for peacetime use while the conti-
nent was more involved with getting
back on its feet by building homes,
factories, and highways. s
The war. however, did have one very
beneficial role for the British. The benefit
was increased metallurgical and design
knowledge that emanated from research
during the war. This knowledge was
quickly adapted to motorcycle design by
the British, and this all helped carry
them to the top in design excellence.
One of the first dramatic advances
after the war was the overhead valve
engine with a hemispherical combustion
chamber. Proven by the AJS 350cc
model in the famous TT races during the
1920 to 1922 era. the new OHV design
was gradually adopted for roadster use
during the middle and late 1920's. This
new design provided a great increase in
performance over the older two-stroke,
side-valve, or parallel valve OHV types,
and the performance of British Hikes
became renowned air over Europe.
Another improvement pioneered by
the racing AJS was the interna! ex-
panding brake system After the fabu-
lous racing successes of the marque
during the early 1920*s there was a...
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