Building a Puch for classic racing.






Through the Dan Jeppesen- Puch project I experienced the qualities
of this Austrian make and during the talks with Albin Sterbenz, he
pointed out the ruggedness of the 337-50 type engine. And rugged it
is compared to any 50cc engine - the Maico being an exception as it
is based on 125cc crankcases. The Puch shares bore and stroke with
the Kreidler as well as a chromed cylinder, but clutch and transmis
sion dwarfs even some 80cc cross bikes. Many Puch models carried
this engine, and two different crankcases were produced to cover
both tube- and pressed steel frames. Here in Denmark, we saw this
engine in the MC50 Super only. More than a hundred of them actually
with 11,2hp engine, and two with 14hp!
First time a 337-50 engine is known to be used for road racing,
were in the Austrian national championship, in early 1974. Same
year Pennti Salonen participated in some world championship races,
with a Tunturi Puch also carrying the same engine.








Pre- production Puch 337-50 engine, sandcasted early version of the Cobra. Notice the symmetrical bolt- pattern for the cylinder/ head and
large, square shape of the cooling fins. Upper surface of crank-
case reveals that this engine also have the left crank mainbearing
lubricated with transmission oil like the 299xxx series seen at
right, which features twin seals at left side of crank.








Update to the Cobra roadrace engine - straight- cut primary gears for use of original as well as Honda style clutch.