Valves And Valve Springs; Removing The Valves; Checking The Valves And Valve Guides - Yamaha XT250X 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
G
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.
MMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMM
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".
LLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLL
2. Remove:
Valve cotters "1"
G
NOTE:
Remove the valve cotters by compressing the
valve spring with the valve spring compressor
"2".
Valve spring compressor
90890-04019
YM-04019

VALVES AND VALVE SPRINGS

3. Remove:
Valve spring retainer "1"
G
Outer valve spring "2"
G
Inner valve spring "3"
G
Valve "4"
G
Valve stem seal "5"
G
Valve spring seat "6"
G
NOTE:
Identify the position of each part very carefully
so that it can be reinstalled in its original place.
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
G
Out of specification → Replace the valve
guide.
Valve-stem-to-valve-guide clearance =
Valve guide inside diameter "a" -
Valve stem diameter "b"
5-18