Yamaha TT-R125EY, Руководство по обслуживанию

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4-34
ENG
CYLINDER AND PISTON
2. Measure:
• Piston-to-cylinder clearance
Piston-to-cylinder clearance
measurement steps:
1st step:
• Measure the cylinder bore C with the cylin-
der bore gauge.
Measure the cylinder bore C in parallel to and
at right angles to the crankshaft. Then, find
the average of the measurements.
Cylinder bore "C" 54.000 ~ 54.019 mm
(2.126 ~ 2.127 in)
Taper limit "T" 0.05 mm (0.002 in)
Out of round "R" 0.05 mm (0.002 in)
"C" = maximum of D
1
~ D
6
"T" = maximum of D
1
, or D
2
-
maximum of D
5
or D
6
"R" = maximum of D
1
, D
3
or D
5
-
minimum of D
2
, D
4
or D
6
• If out of specification, replace the cylinder,
and replace the piston and piston rings as
set.
2nd step:
• Measure the piston skirt diameter P with a
micrometer.
a
5 mm (0.20 in) from the piston bottom edge.
Piston size P
Standard 53.977 ~ 53.996 mm
(2.1251 ~ 2.1258 in)
• If out of specification, replace the piston and
piston rings as a set.
3rd step:
• Calculate the piston-to-cylinder clearance
with following formula.
Piston-to-cylinder clearance =
Cylinder bore "C" -
Piston skirt diameter "P"
Piston-to-cylinder clearance:
0.020 ~ 0.026 mm
(0.0008 ~ 0.0010 in)
<Limit>: 0.15 mm (0.006 in)
TIP