Fig.
1-48
\._,
Fig.
1-49
Fig.
1-50
1
1-C-22
. Checking
Main
Journal and Crankpin
Clean the crankshaft thoroughly with a suitable so
l-
vent and blow
out
the oil passages with compressed
air.
In
spect the crankshaft for crack, scratch and t
he
o
il
passages for clog.
Measure the diameter
of
each crankpin and main journal
with a micrometer.
If
the wear
is
more than 0.05
mm
(0.0020 in), the crankshaft should be ground to the
undersize
of
0.25, 0.50 and 0.75
mm
(0.010, 0.020 and
0.030 in) or replaced.
The standard diameter
of
the crankpins and main
journals are shown in the following table.
Crankpin
53
- 0.045 (2 0866 - 0.0018 .
- 0.060
mm
· - 0.0024 m)
Main journal
63 - 0.045 (2 4804 - 0.0018 .
- 0.060
mm
• - 0.0024
m)
1-C-
23
. Checking Crankshaft Alignment
To
check alignment, mount the crankshaft
on
the
"V"
blocks and apply a dial indicator. Slowly rotate
the crankshaft and note the reading on the dial indi-
cator. The maximum allowable run-out
is
0.
03
mm
(0.00
12
in).
If
it is not within specification, replace the crankshaft
with new one.
1-C-24.
Main Bearing
The main bearings are classified into 2 types according
to the shape
as
shown in Fig.
1-50
.
The main bearings are available in the standard size
and undersize
of
0.2
5,
0.50 and 0.75
mm
(0.010,
0.020 and 0.030 in).
Inspect the bearings carefully for wear, scoring, flaking
or
any damage.
If
any
of
these conditions exists, replace
with new bearings.
Each bearing consists
of
Lwo
halves and should be
replaced
as
a set.
1 : 14
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