III.
DESCRIPTION OF THE MACHINES
The Maico MC 250, 400, 440 and 501 ccm Motorcycles are very high performance competition
motor-
cycles which are designed for off-road use in difficult
terrain or on a moto-cross race track.
A.
MOTOR
1.
CYLINDER
The cyl inder is a special moto-cross cyl inder con-
structed of a light alloy material with a shrunken
cylinoer sleeve. The cooling fins are arranged
radially for better cooling even at low speeds. The
cylinder is fastened to the crank casesby four
8 x 28 mm studs. Between the cylinder and main
casesis a paper gasket 0.3 mm thick.
2.
CYLINDER HEAD
Is also constructed of a light alloy material. The
cooling fins are again arranged radially with five-
8 mm or 10 mm studs mounting it to the cylin-
der. The cylinder head gasket is made of soft cop-
per (0.6 mm thick).
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3. Cylinder piston, Cylinder head
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3.
THE PISTON
440 CC
8195
82.10
8225
to 83.00
400 CC
7695
77.10
77.25
t078.00
250 CC
66.95
67.10
67.25
to 68.00
The MAHLE piston is forged of a special piston alloy containing a large amount of silicon. With "L"
shaped piston ring in the 250, 440 and 501. An "L"
shaped and a rectangular piston ring is used in the
400. The piston clearance in the cylinder measures 0.05 to 0.07 mm. The piston oversizes are available
in approximately
0.15 mm intervals .
Example:
Std.
1st over
2nd over
Pistons other than MAH LE are not recommended.
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4.
CRANKSHAFT AND CONNECTING ROD
The crankshaft halves are turned on a lathe from
rough forgings. After careful machine finishing,
they are heat treated for better case hardening
(they are also tempered after being heat treated).
The right half or magneto half is tapered. The
left half has a key way or splines to attach the
primary drive sprocket. The connecting rod is
forged as well. The journal for the needle bea.
rings is caged. The radial play of the big end
bearing is 0.03 mm to 0.04 mm. The play of the
wrist pin to the wrist pin bearing is 0.002 to
0.005 mm.
4. Crankshaft, Bearings, Seals
