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4-8 ENGINE TOP END
Cylinder Wear Inspection
Measure the cylinder inside diameter when the cylinder
is cold (room or ambient temperature).
Visually Inspect the inside of the cylinder for scratches
and abnormal wear.
If the cylinder is damaged or badly worn, replace it with a
Since there is a difference in cylinder wear in different di-
rections, take a side-to-side and a front-to back measure-
ment shown in the figure.
If any of the cylinder inside diameter measurements ex-
ceeds the service limit, the cylinder must be replaced with
a new one since the ELECTRO FUSION cylinder cannot
be bored or honed.
Cylinder Inside Diameter
44.500 ∼ 44.515 mm, and less than
0.01 mm difference between any two
44.64 mm, or more than 0.05
mm difference between any two
[A]: 15 mm
Piston Diameter Measurement
Measure the outside diameter [B] of the piston 6.0 mm
[A] up from the bottom of the piston at a right angle to the
direction of the piston pin.
If the measurement is under the service limit, replace the
44.453 ∼ 44.468 mm
[A]: 6.0 mm
Piston/Cylinder Clearance Inspection
The piston-to-cylinder clearance is measured whenever a
piston or cylinder is replaced with a new one. The standard
piston-to-cylinder clearance must be adhered to whenever
the cylinder is replaced.
If only a piston is replaced, the clearance may exceed the
standard slightly. But it must not be less than the minimum,
in order to avoid piston seizure.
The most accurate way to find the piston clearance is
by making separate piston and cylinder diameter measure-
ments and then computing the difference between the two
values. Measure the piston diameter as just described, and
measure the cylinder diameter at the very bottom of the
0.042 ∼ 0.052 mm