Yamaha XT 600 AC Service Manual page 130

INSPECTION AND REPAIR
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1
ENG
1'-1
4-24
3. Measure:
-Valve seat width
®
Out of specification
-+
Reface valve seat.
Valve seat width:
1.0"'-'1.2 mm (0.04"'-'0.05 in)
Exhaust
***********************
Measurement steps:
• Apply the Mechanic's bluing dye (Dykem)
CD
to t he valve face .
• Install the valve into the cylinder head.
• Press the valve through the valve guide and
onto the valve seat to make a clear pattern.
• Measure the valve seat width. Wherever the
valve seat and valve face made contact,
bluing will have been removed .
• If the valve seat width is too wide, too nar-
row, or seat has not centered, the valve seat
must be refaced.
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4. Reface:
-Valve seat
Use a 30°, 45° and 60° valve seat cutter
CD.
Valve seat cutter:
Pi N.
YM-91043
When twisting cutter, keep an even down-
ward pressure (4-5 kg) to prevent chatter
marks.