Yamaha F200B, Service Manual

Page: 346 / 579

7-87
POWR
Power unit
TIP:
The figures are for reference only. Depend-
ing on how the parts are assembled, the
actual measurements may not be within the
specified ranges.
Checking the piston ring groove
1. Measure the piston ring grooves.
Replace the piston if out of specification.
Checking the piston ring side
clearance
1. Measure the piston ring side clearance.
Checking the piston pin boss inside
diameter
1. Measure the piston pin boss inside diam-
eter.
TIP:
When measuring the piston pin boss inside
diameter, do not measure it at the oil grooves
b
or ring groove
c
.
Checking the piston pin
1. Measure the piston pin outside diameter
a
.
Measuring point
a
(reference data):
20.0 mm (0.8 in)
Piston ring end gap
b
(reference data):
Top ring:
0.200–0.300 mm (0.0079–0.0118 in)
Second ring:
0.300–0.450 mm (0.0118–0.0177 in)
Oil ring
0.150–0.600 mm (0.0059–0.0236 in)
Piston ring groove:
Top ring
a
:
1.230–1.250 mm (0.0484–0.0492 in)
Second ring
b
:
1.220–1.240 mm (0.0480–0.0488 in)
Oil ring
c
:
2.510–2.530 mm (0.0988–0.0996 in)
a
b
c
Piston ring side clearance:
Top ring
a
:
0.035–0.050 mm (0.0014–0.0020 in)
Second ring
b
:
0.030–0.070 mm (0.0012–0.0028 in)
Oil ring
c
:
0.040–0.130 mm (0.0016–0.0051 in)
Piston pin boss inside diameter
a
:
21.021–21.031 mm (0.8276–0.8280
in)
a
b
c
b
b
c
a