BMI Classic Motorcycles
Between 1934 and 1937 BMI
produced auxiliary engines for use on a bicycle.
The ca. 80cc engine had an automatic intake
valve, a concept popular to about 1910; the
intake petrol/air mixture is sucked into the
cylinder when the piston travels downwards.
Some 3500 of these engines were produced,
although the design was very outdated.
In 1937 it was decided to
design a new engine, a 175 cc sidevalve concept
and completely new cycle parts; a proper lightweight
motorcycle. It was assumed that this design
had never got further than the drawning table;
as it appears now this machine is the prototype
of the new design.
It recently turned up among
some machines that had been in storrage at
the National Dutch Automobile Museum for years
and were sold off as surplus items.
||1937 BMI Zk Prototype, 175cc
||This machine has a Burman 3-speed gearbox
and high level exhaust and silencer. Crankcase
and cylinder are integrated in one cast-iron
piece, cylinder head is aluminium and there
is an outside flywheel. The sidevalves are
placed in front of the engine. The BMI logo
is visible on the tank, the headstock and
the heat protection shield over the exhaust.
Truly a rare and remarkable piece of Dutch