|The water cooled
Lewis are probably best remembered for their water-cooled
motorcycles, which were built in a variety of forms between 1905 and the very early 1920s.
The water cooled era at Lewis began in early 1905 with experiments using water-cooled De
Dion Bouton motors. Later that year Vivian Lewis and T.P. O'Grady lodged an Australian
patent (4275/1905) for An improved method of and means for cooling the cylinders of
motor bicycles, in which they laid out their ideas for a water cooled motorcycle.
There has been much conjecture about the origin of the
motors used for the water-cooled machines. At this stage, the origin of the earliest
machines (with atmospheric inlet valves) is still uncertain, and although Lewis lore might
suggest Blumfield origin, I think we might in time find a link with the Stevens Motor Manufacturing Company who were responsible for the
1907-on 3 h.p. side-valve motor. From 1911 (or possibly late 1910), engines were sourced
from F.E. Baker (Precision).
As I rebuilt my c1908
water-cooled motor, I developed a scepticism that such a motor could have been built
by a UK manufacturer. There is an element of "roughness" about the original
build of the motor that is more in line with local manufacture, but given the parlous
state of Stevens at the time it could just be an example of production under less than
optimal conditions. Although unlikely, we should probably leave open the possibility that
the Lewis motors were copies of the Stevens engine.
Note that the "Lewis" badge seen on the crank
case of most Lewis motors is riveted on (almost invisibly) for all the pre-1911 motors.
"Lewis" is cast in to the timing covers of the Precision engines, and into
magneto chain cases when present.
||In March 1905, Lewis exhibited a pair of
water-cooled motorcycles, "the first constructed in this state".
One used a 3 1/2 h.p. De Dion Bouton motor (most likely similar to the one shown
here) and the other a 3 h.p. motor from the same manufacturer. These two machines should
be considered the forerunners to the long line of Lewis water-cooled motorcycles. It is
not known how many De Dion-engined machines were built. Does anyone have an illustration
of these early Lewis machines?
||In September 1905, it was reported that the
Lewis Motor Works had just finished a 2 1/2 h.p. water-cooled motorcycle "the engine
of which was made on the premises". Shown is the motor of the water-cooled Lewis once
owned by N. Jackson. This machine used the early-style radiator with curved corners and
hot water inlet from the rear. Note the absence of writing on the motor. The exhaust lift
lever pivots at the rear of the cylinder, providing a rather tortured path for the
exhaust-lift rod. If this is not the prototype water-cooled Lewis, it is certainly a very
early example, c1905. This or a similar machine was snapped in the white garage.
||A production engine, c1906. Other than the Lewis
plate on the crank case, the inscription on the magneto chain cover (LEWIS MOTOR TYPE, 5,W
ADELAIDE S.A.), and the reversal of the exhaust lift arm, not too much seems to have
changed from the model above. This machine is featured as photograph 09 in the Lewis Album, and similar
machines are seen in the white garage. The
manufacturer of the motor is still an open question.
||The first of the side-valve motors appeared in
1907, although this illustration is from the 1909
catalogue. This motor was a product of the Stevens Motor
Manufacturing Company. At some point in the evolution of this motor, both the inlet
and exhaust ports grew is size. On the later motors, the exhaust exit was a little closer
to the horizontal. A key identifier for this motor is the somewhat heart-shaped timing
chest, whose cover was bronze on the earliest models, but later became either aluminium,
or, in at least one case, steel.
||A mystery motor, characterised by the
"U" shaped timing chest and a water drain cock on the front of the water jacket
behind the exhaust pipe. The cylinder casting and valve lifter detail are strikingly
similar to the Stevens engine. At a guess, the date would be
c1910, just before the introduction of the Precision motor.
||On the first of the water-cooled Precision
motors, the hot water outlet was screwed into the water jacket between the valves. Aside
from the steep angle of the exhaust port, there are many similarities between the first "Precision" cylinders and those of earlier
Stevens models. This is the 3 1/2 h.p. motor as shown in the 1912
Lewis catalogue. By 1914 (see below), the outlet had moved to in front of the exhaust
valve. The rather absurd Brown & Barlow carburettor was introduced c1912 for the Lewis
model with the fuel tank behind the seat tube.
||The 1910-on Precision motor was offered in two
sizes: this is the smaller of the two as it appear in 1914. Sometimes referred to as the
"narrow valve" Precision, it had bore and stroke of 75 x 86 mm giving 380 cc,
and was rated at 3 h.p. The illustration is from the 1914 Lewis catalogue, but seems to date
from a year or two earlier. That said, there were relatively few changes during the
late-1910 - c1916 production life of the motors.
||The larger Precision motor
(85 x 88 mm giving 499 cc, rated at 3 1/2 h.p.) was offered in parallel with the 3
h.p. Naturally enough, it is sometimes referred to as the "wide valve" motor.
The illustration is from the 1914 Lewis
catalogue. Changes from the earlier version were few, but included repositioning the
water outlet to in front of the exhaust valve (where the manifold was mounted to a
flange), and a rounding of the bottom of the timing chest.
||A photograph survives of a Lewis machine,
stripped for racing, fitted with the water-cooled
Green Precision motor. The year of manufacture is not known, but is likely to be
c1914. The illustration here comes from a war time edition of Motorcycles and How to
Manage Them, as no record of this motor has yet been found in Lewis literature.
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