1964 Maico 250 Scrambler - 4-Page Vintage Motorcycle Road Test Article

Description

1964 Maico 250 Scrambler - 4-Page Vintage Motorcycle Road Test Article
Original, Vintage Magazine article
Page Size: Approx. 8" x 11" (21 cm x 28 cm) each page
Condition: Good
All new motorcycles make for good
conversation, but there is nothing
quite as satisfactory as an up-dated ver-
sion of a motorcycle that was pretty good
last year, and that fairly accurately de-
scribes the new Maico Scrambler that we
recently tested. At first glance, there is
nothing much very different about the
present model, as compared to the one
that preceded it, but it is substantial im-
provement over the previous bike none-
theless. That is not to say that last year’s
Maico was a bad motorcycle; it is just
that the one now available is such a very
good one.
The biggest visible change is in the
engine. The same bore and stroke have
been retained, and the same crankcase,
but there is a new light-alloy cylinder that
gives improved cooling and an increase in
power. The new cylinder is deeply finned,
with the deepest part of the finning lo-
cated around the transfer ports, which
keeps them cool and thereby both mini-
mizes cylinder distortion and helps power
output. Also in the interest of minimizing
distortion are the slots in the fins near
the exhaust port. The exhaust port area
will be a lot more hot than the rest of the
cylinder, no matter what is done, and the
slots prevent both heat and distortion
from spreading. Maico had a similar alloy
cylinder before, but that cylinder was
somewhat different, with a hard-chromed
bore. The latest cylinder has a centrifugal-
ly-cast iron liner, which is much more
durable. Being centrifugally-cast, it is very
dense and, entirely free of casting flaws;
and is thick enough to brace the main
cylinder casting against heat-produced dis-
tortion. Also, because it is so thick, it can
be rebored several times — all the way
from the standard 67mm clear out to
7 1mm.
Most two-stroke engines have oil-mist
lubrication to the entire crank assembly:
wrist-pin, rod and main bearings; not so
the Maico. The ball-type main bearings are
separated from the crankcase by spring-
backed neoprene seals, and lubricated
with oil from the primary case. The pri-
mary-side bearing is fed more or less di-
rectly; the bearing over on the other side
of the crankcase is fed by oil that is
thrown up into a cast-in trough and runs
through drilled passages to the bearing.
This is a bit more difficult to manufac-
ture than the conventional arrangement,
but it gives a slightly smaller crankcase
volume (quite important in terms of max-
imum power) and it insures that the
bearings will get enough oil. Even if the
owner fails to get enough oil mixed with
the gasoline and ruins the piston and con-
necting rod bearing, he will at least have
the comfort of knowing that it will not
be necessary to replace the main bearings
as well.
One of the things we were less than
enthusiastic about on the last Maico we
tested was the rather skimpy provision for
air filtration. The carburetor was fitted
with a small “gravel strainer” filter that
might have kept low-flying butterflies out
of the engine, but certainly not that oh-
so-destructive dust. Now, the carburetor
draws from a large air box to which a...
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