Yamaha TT600R Service Manual page 226

INSPECTION AND REPAIR
3. Measure:
•
Valve seat width (a)
Out of specification
Valve seat width (a):
Intake:
Exhaust:
Measurement steps:
•
Apply Prussian blue (Dykem) to the valve
seat.
•
Install the valve in the cylinder head.
•
Press the valve onto the housing through the
guide to leave a clear outline.
•
Measure the width of the valve seat. Where
there is contatc between valve and seat the
Prussian blue is wiped away.
•
If the valve seat is too narrow, wide or off-cen-
tre, the valve seat must be renewed.
4. Renew:
•
Valve seat
Use the special tool (1) to renew the valve
seat with 30°, 45° and 60° mills.
CAUTION:
Turning the cutter, maintain uniform pressure
(about 4-5 kg) to avoid leaving marks on the
valve seat.
5-24
ENG
Renew valve seat.
1.0 ~ 1.2 mm
<Limit>: 1.8 mm
1.0 ~ 1.2 mm
<Limit>: 1.8 mm