Checking The Valves And Valve Guides - Yamaha YP250R 2005 Service Manual

VALVES AND VALVE SPRINGS
3. Remove:
NOTE:
Identify the position of each part very carefully
so that they can be reinstalled in their original
place.
EAS00239
CHECKING THE VALVES AND VALVE
GUIDES
The following procedure applies to all of the
valves and valve guides.
1. Measure:
5 - 21
• upper spring seat 1
• outer valve spring 2
• inner valve spring 3
• valve 4
• valve stem seal 5
• lower spring seat 6
• valve-stem-to-valve-guide clearance
Out of specification → Replace the valve
guide.
Valve-stem-to-valve-guide clearance =
Valve guide inside diameter a –
Valve stem diameter b
Valve-stem-to-valve-guide clear-
ance
Intake
0.010 ~ 0.037 mm
(0.0004 ~ 0.0015 in)
<Limit>: 0.080 mm (0.0031 in)
Exhaust
0.025 ~ 0.052 mm
(0.0010 ~ 0.0020 in)
<Limit>: 0.100 mm (0.0039 in)
ENG