Checking The Valves And Valve Springs - Yamaha YXR70FX Service Manual

VALVES AND VALVE SPRINGS
3. Remove:
• valve spring retainer 1
• valve spring 2
• valve 3
• valve stem seal 4
• valve spring seat 5
TIP:
_
Identify the position of each part very carefully
so that it can be reinstalled in its original place.
EBS00240
CHECKING THE VALVES AND VALVE
SPRINGS
The following procedure applies to all of the
valves and valve guides.
1. Measure:
• valve-stem-to-valve-guide clearance
Stem-to-guide clearance =
valve guide inside diameter a -
valve stem diameter b
Out of specification → Replace the valve
guide.
4 - 29
ENG
Stem-to-guide clearance
Intake
0.010 ~ 0.037 mm
(0.0004 ~ 0.0015 in)
<Limit>: 0.08 mm (0.0031 in)
Exhaust
0.025 ~ 0.052 mm
(0.0010 ~ 0.0020 in)
<Limit>: 0.10 mm (0.0039 in)