Yamaha 2009 TT-R125 Wartungs-Handbuch Seite 302

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.
TIP
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"
Taper limit "T"
Out of round "R"
"C" =
"T" =
"R" =
• 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.
Standard
• 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:
4-34
ENG
54.000 ~ 54.019 mm
(2.126 ~ 2.127 in)
0.05 mm (0.002 in)
0.05 mm (0.002 in)
maximum of D ~ D
1
maximum of D , or D
1
maximum of D or D
5
maximum of D , D
1 3
minimum of D , D
2 4
Piston size P
53.977 ~ 53.996 mm
(2.1251 ~ 2.1258 in)
0.020 ~ 0.026 mm
(0.0008 ~ 0.0010 in)
<Limit>: 0.15 mm (0.006 in)
6
-
2
6
or D -
5
or D
6