Valves And Valve Springs; Removing The Valves; Checking The Valves And Valve Guides - Yamaha XG250 Service Manual

EAS24280

REMOVING THE VALVES

The following procedure applies to all of the
valves and related components.
NOTE:
Before removing the internal parts of the cylin-
der head (e.g., valves, valve springs, valve
seats), make sure the valves properly seal.
1. Check:
Valve sealing
●
Leakage at the valve seat → Check the valve
face, valve seat, and valve seat width.
Refer to "CHECKING THE VALVE SEATS"
on page 5-20.
▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼
a. Pour a clean solvent "a" into the intake and
exhaust ports.
b. Check that the valves properly seal.
NOTE:
There should be no leakage at the valve seat
"1".
▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲
2. Remove:
Valve cotters "1"
●
NOTE:
Remove the valve cotters by compressing the
valve spring with the valve spring compressor
and the valve spring compressor attachment "2".

VALVES AND VALVE SPRINGS

3. Remove:
Upper spring seat "1"
●
Inner valve spring "2"
●
Outer valve spring "3"
●
Valve "4"
●
Lower spring seat "5"
a ●
Valve stem seal "6"
●
NOTE:
Identify the position of each part very carefully
so that it can be reinstalled in its original place.
1
EAS24290
CHECKING THE VALVES AND VALVE
GUIDES
The following procedure applies to all of the
valves and valve guides.
1. Measure:
Valve-stem-to-valve-guide clearance
●
Out of specification → Replace the valve
guide.
5-18
Valve spring compressor
90890-04019
YM-04019
Valve spring compressor attach-
ment
90890-01243
Valve spring compressor adapter
(26 mm)
YM-01253-1
1
3
6
2
1
2
5
4