Belgian firm of Fabrique Nationale has always made interesting motor cycles, and up till
1939 their products were raced with fair success on the Continent. In the golden era of
motor cycling in Australia - 1926 to 1932 - quite a few F.N.'s were brought into this
country, both fours and singles. The couple of highly tuned 350 c.c. models that were
raced in Western Australia did very well against the very hot competition then existing in
that class. They had an extremely massive engine (with chain driven overhead camshaft), in
a graceful and rather nice-handling double-cradle frame. One of these, after a very hard
life, now spends its declining years in Kalgoorlie, where it seems to belong to nobody in
particular, but is borrowed by any local clubman who should find himself without a mount
for any special event. In spite of being fed a variety of witches' brews in the way of
fuel, the old "nuisance"' has never disgraced herself.
However, although the F.N.'s even of those times are practically
forgotten now, they were very modern when compared with that illustrated here. Just when
this machine first saw the light of day is a matter of conjecture, but when purchased in
1911, she was very secondhand, so at the most charitable estimate she would be a 1910
model. But the atmospheric inlet valves would seem to indicate a greater age, and the
writer's guess is that "she's forty if she's a day."
Nowadays, a four cylinder motor cycle doesn't get a second look, and
shaft drive is here to stay. But a combination of these two features is still very rare.
And more so is a small capacity straight four.
This veteran has four air-cooled cylinders, each cast separately.
Heads, of course, are integral with the barrels.
Centrelines of numbers 1 and 2, 2 1/2 inches apart, 2 and 3 at 3
inches, and 3 and 4 2 1/2 inches. Side exhaust valves are used, actuated by a camshaft on
the off side. Access to these can be had by first removing the inlet manifold. Cylinder
dimensions are about 50 m.m. bore and 60 m.m. stroke, giving a capacity of some 118 c.c.
per cylinder, and 472 c.c. for the four. The crankshaft is carried on three main bearings.
Big ends are very broad, being a little over an inch wide. The big end caps are each held
to the rod by four small cheesehead screws.
|Offside of the engine showing the maze of
manifolds and the method of mounting the engine to the frame. The magneto is in an
The carburettor now fitted is not the original instrument, and is a
B. and B., a very modern-looking article, although it was installed about 1912. It
supplies the mixture through a downdraught manifold, which is a masterpiece of
snake-charming. This bears a quantity of solder, rather naturally, as it must have had
considerable fatigue on account of its attachment to four separate cylinders and carrying
the heavy carburettor. The bore of each manifold branch is approximately seven-sixteenths
of an inch.
The 5/8-inch bore exhaust pipes have a rather elegant curve down to
the expansion box, from which a venturi-shaped tailpipe emerges. From this venturi runs a
pipe to the crankcase breather on the other side of the engine. The designer must have
been keen on crankcase ventilation.
The Belgian Bosch FN 10 magneto is driven from the front end of the
crankshaft, and the distributor from the front end of the camshaft. These components are
just in the right position to collect the lot on a rainy day.
The flywheel is a very light shell enclosing the clutch, which has a
plurality of plates. Clutch operation is by a Bowden-operated quick-thread device.
A spur wheel, outside the flywheel, drives the pinion on the front
end of the propeller shaft. Only one ratio is available.
Front forks are of the bottom-link type, broadly reminiscent of the
earlier Harley Davidson. The springs both impact and rebound, are neatly housed in
telescopic covers. The upper linkage carries a bracket to accommodate the carbide lamp
The upper portion of the frame is on the general lines of any
contemporary machine, but the front down tube forks into two elliptical section cradle
tubes, between which the engine is slung. At the front end of these tubes are the
(apparently non-standard) footrests - way off in the dim distance when viewed from the
saddle. This saddle, a very spartan affair, is 36 inches from the ground, to allow
vigorous use of the pedalling gear as and when.
There is no offside chainstay, the propeller shaft housing.
performing the function of a normal chainstay. There is a detachable bar above this - a
solid piece of black-smithing in half-inch round, which would seem to indicate that a
previous owner didn't fancy relying on this torque-tube business to hold the back end of
the frame true.
The F.N. was located in Broken Hill, forgotten under many years' accumulation of odd
building material and tools. The writer is greatly indebted to Mr. Dave Reynolds, an old
resident of the town, for his kindness in handing over this magnificent piece of motor
cycling history. Too few of such machines have been preserved intact, and to a student of
motor cycle design the possession of one is most gratifying. The search for these
"old and rares" is a protracted and arduous process, in the course of which one
may find much chaff and very little grain. But no collection could have been a more worthy
nucleus than this fine old F.N.