For most people, the Honda race history
starts with the 1959 entry of the Honda team in the Isle of Man TT.
However, although practically unknown in Europe at the time, Japan
in those days had a fast growing motorcycle industry, but their models
looked very old fashioned, and the ones that did look (more or less)
modern were often straight copies of German, British or American (read
Harley) motorcycles.
Honda, even in those days already a very
big motorcycle manufacturer, faced the problem that it would be very
difficult to sell its bikes worldwide. Japanese products in general
had a bad reputation regarding quality, based on Japanese pre-war
products (the camera industry in Japan faced the same problem). So
how do you overcome such a problem? By proving to the world, that
your engineering and the resulting products are superior -in the case
of motorcycles by winning Grand Prix with them.
1954
Soichiro Honda had decided, in the beginning of the fifties,
that one day he would compete in the famous TT of Man, and in 1954
a 220cc single cylinder prototype racer was developed
In that same year, Soichiro took a trip to Europe, watched the
TT, and was very disappointed: the then European 250cc racing bikes
had on average more than double the power of his prototype. He also
used his trip to go on a buying spree; he bought rev counters, carburettors,
rims, spark plugs and what have you. The story goes that, upon arrival
at the airport for his return flight to Japan, his luggage was overweight
and he was not allowed to check in. Honda opened his suitcases,
took out all his clothing, put on as much as possible on top of
each other, filled his pockets with parts, and that did the trick,
whereupon he remarked to the airport personnel: "You are idiots!
Now I'm allowed in, but the total weight in the plane is exactly
the same!" He was quite right, of course; they should set a limit
to the weight of passengers together with their luggage, not to
luggage alone.
A couple of years later, Honda had developed 250 and 305cc twins
with a single OHC, used in national events
By 1959, Honda decided he was ready to take on the rest of the
world, and the first Japanese team arrived on the Isle of Man.
the
1954 220cc
1957 SOHC
.......
A legend was born ........
1959
June
1959, TT of Man
Honda arrives on Man with 5 riders, 4
Japanese and one American. They bring along five 125cc racing motorcycles
and four training bikes, plus enough spares and tools to set up
a self sufficient workshop - a very professional approach.
The racers, with the type designation RC142, have open spine frames,
in which the engine is a stress bearing part, with leading link
front and swing arm rear suspension. The engine is a four stroke
twin with the cylinders slightly inclined forward under 6 degrees,
with DOHC, driven by a vertical shaft with bevel gears on the left
hand side of the engine, and from there with gears to the camshafts.
1959
125cc RC142
tttttttttttttttttttttttttttttttttttttttttttttttt
There
are two valves per cylinder, as can be clearly seen from the position
of the spark plugs in the picture.When during practice it
becomes clear that the bikes are lacking in power, four-valve heads
are flown in from Japan. Bore and stroke are 44 x 41 mm for a capacity
of 124.6 cc, and with a compression ratio of 10.5 : 1, 18.5 bhp is
developed at 13,000 rpm; maximum rpm is 14,000. The valve angle is
40 degrees for the inlet valves and 44 degrees for the exhaust valves;
spark plugs for the four-valve heads are 10 mm. Carburation is by
flat-slided Kei-hin carburettors with remote float chambers. Ignition
is by magneto, driven by the inlet-camshaft. Lubrication is by wet-sump
system, carrying 2 litres of oil. The gearbox contains 6 speeds, and
the total weight of the bike is 87 kg. The wheelbase is 1265 mm. In
the TT, the bikes finish 6th, 7th, 8th and 11th, earning Honda the
team prize. The American rider drops his bike and doesn't finish.The
race proved that the Honda's were reliable, but not yet fast enough,
although the results no doubt would have been better if top European
riders, well acquainted with the TT course, would have ridden the
bikes. After the race, Honda's team returned to Japan, having spent
on this one trip as much as most factories would spend on a whole
season of racing.
1959 125cc RC142 Engine
It
showed the world that they meant business, and that they could expect
them to be back.
Copies?
Often
it has been written that the Honda 125cc racers were copies of the
NSU Rennmax twins. That, in my opinion, is nonsense, and the people
saying it don't know what they're talking about. Apart from the fact
that Honda in far away Japan had absolutely no access to the very
secret data of the NSU racing department, the Rennmax was 250, the
Honda 125 cc; the Rennmax had its bevel shaft driving the inlet camshaft,
the Honda's shaft ended between the gears. The NSU had coil and battery
ignition, the RC142 got its sparks from a magneto, and had four valves
against the two of the NSU, which had dry sump oiling whereas the
Honda had a wet sump. So the only common points were the bevel shaft
and gears, and they were not identical, and the fact that it was a
four stroke twin. Well, the slightly earlier Simson 250cc racers from
East-Germany and 250cc Mondial racers from Italy had the same characteristics
(bevel shaft and gears, four-stroke twin), and nobody ever called
them NSU copies. It shows the bias against the Japanese designs, which
even now still exists.
The
250 cc Four RC160
The same year, 1959, Honda announced that they had produced
a 250cc four-cylinder along the same lines as the 125cc twin.The idea of a 250 four was not a new one; during 1939-40, Gilera,
Bianchi and Benelli had built supercharged 250 fours, the Benelli
water-cooled, the other two air-cooled. The outbreak of the war
prevented the use of those bikes, and when racing was resumed
after the war, supercharging was banned, making them redundant.
It was only in 1960, one year after the Honda four was introduced,
that Benelli again fielded a 250cc four.
The Honda four, designated the RC160, had the same
specifications as the 125cc twin, but the cylinders were now upright
instead of being inclined, and the ignition was changed from magneto
to battery with four coils. Claimed power output was 35 bhp at
13,000 rpm, with the same maximum engine speed of 14,000 rpm as
the twin. The engine had a five-speed gearbox and weighed 58 kg.
The cycle parts were nearly identical with the 125cc twin, the
wheelbase being longer by 45 mm at 1310 mm, and the total weight
of the bike was 124 kg. The RC160 was never raced outside of Japan
and, being often raced on unpaved roads, was mostly shown without
a fairing and with semi - knobbly tyres.
1959 250cc RC160
1959 250cc RC160
left and right - The 1959 250cc RC160 Engine
General
information on Honda racing motorcycles
All the Honda racing motorcycle models to be discussed further
have a number of things in common. They are all four strokes and,
with the exception of the one-off RC144 125 cc twin and RC112 50
cc twin, all have four valves per cylinder; so I won't mention the
fact of four valves per cylinder every time again.
The bhp mentioned is the horsepower at the rear chain wheel;
the dynamometer is sitting at the location of the rear wheel. This
was confirmed by Nobby Clark, the erstwhile Honda race mechanic.
It's the most logical place to measure the power; contrary to the
crankshaft power, it gives a true indication of the power that's
available for propelling the bike. This power is approximately 15
% lower than the crankshaft power. The development of the Honda
racers followed a certain pattern, going through a test phase in
three stages. First the lubrication system is checked, so that any
part that could suffer a premature death through a deficiency of
oil can be supplied with a bit more of it. Once that is found right,
the heat generation and cooling is checked. With a little bit of
oil here and an extra cooling fin there, the engine can be made
thermically healthy. The last stage is measuring the power. If this
is not sufficient, cam timing and inlet / exhaust lengths are changed,
and the whole story starts again. In general, with racing motorcycles,
the maximum engine speed is approximately between 5 and 10 % higher
than the speed for maximum power. For very short periods, an even
higher speed is permitted, e.g. during changing down.
