ENG
VALVES AND VALVE SPRINGS
3. Remove:
• valve spring retainer
1
• outer valve spring
2
• inner valve spring
3
• valve stem seal
4
• valve spring seat
5
• valve
6
Identify the position of each part very carefully so
that it can be reinstalled in its original place.
NOTE:
CHECKING THE VALVES AND VALVE
GUIDES
The following procedure applies to all of the valves
and valve guides.
1. Measure:
• clearance between the stem and the valve
guide
Out of specification
-->
Replace the valve
guide.
clearance between the stem and the valve
guide = valve guide inside diameter
a
- valve
stem outside diameter
b
.
Clearance between the stem and the
valve guide
Intake
0.010 ~ 0.037mm
(0.0004 ~ 0.0015 in)
<limit>: 0.080mm
(0.0032 in)
Exhaust
0.025 ~ 0.052mm
(0.0010 ~ 0.0020 in)
<limit>: 0.100mm
(0.0040 in)
6
5
4
3
2
1
a
b
5-24
Summary of Contents for YBR250 2007
Page 1: ...YBR250 SERVICE MANUAL 5D1 F8197 E0 2007 ...
Page 2: ......
Page 359: ...YAMAHA MOTOR DA AMAZÔNIA LTDA ...
