Yamaha YZF-R1S Service Manual - Eng
5-30
VALVES AND VALVE SPRINGS
ENG
NOTE:
NOTE:
EAS00240
CHECKING THE VALVE SEATS
The following procedure applies to all of the
valves and valve seats.
1. Eliminate:
Scarbon deposits
(from the valve face and valve seat)
2. Check:
Svalve seat
Pitting/ wear
! Replace the cylinder head.
3. Measure:
Svalve seat width
a
Out of specification
! Replace the cylinder
head.
Valve seat width
Intake: 0.9
X 1.1 mm
Intake:
(0.0354
X 0.0433 in)
Exhaust: 0.9
X 1.1 mm
Exhaust:
(0.0354
X 0.0433 in)
a. Apply Mechanic’s blueing dye (Dykem)
1
onto the valve face.
b. Install the valve into the cylinder head.
c. Press the valve through the valve guide and
onto the valve seat to make a clear impres-
sion.
d. Measure the valve seat width.
Where the valve seat and valve face contacted
one another, the blueing will have been re-
moved.
4. Lap:
Svalve face
Svalve seat
After replacing the cylinder head or replacing
the valve and valve guide, the valve seat and
valve face should be lapped.