Checking The Valve Seats - Yamaha YZFR6V Service Manual

Valve guide remover (ø4.5)
90890-04116
Valve guide remover (4.5 mm)
YM-04116
Valve guide installer (ø4.5)
90890-04117
Valve guide installer (4.5 mm)
YM-04117
Valve guide reamer (ø4.5)
90890-04118
Valve guide reamer (4.5 mm)
YM-04118
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3. Eliminate:
• Carbon deposits
(from the valve face and valve seat)
4. Check:
• Valve face
Pitting/wear → Grind the valve face.
• Valve stem end
Mushroom shape or diameter larger than the
body of the valve stem → Replace the valve.
5. Measure:
• Valve margin thickness D "a"
Out of specification → Replace the valve.
Valve margin thickness D (intake)
0.90–1.10 mm (0.0354–0.0433 in)
Limit
0.8 mm (0.03 in)
Valve margin thickness D (ex-
haust)
1.10–1.30 mm (0.0433–0.0512 in)
Limit
1.0 mm (0.04 in)
6. Measure:
• Valve stem runout
Out of specification → Replace the valve.
NOTE:
• When installing a new valve, always replace
the valve guide.
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5-21
VALVES AND VALVE SPRINGS
• If the valve is removed or replaced, always re-
place the valve stem seal.
Valve stem runout
0.040 mm (0.0016 in)
EAS24300

CHECKING THE VALVE SEATS

The following procedure applies to all of the
valves and valve seats.
1. Eliminate:
• Carbon deposits
(from the valve face and valve seat)
2. Check:
• Valve seat
Pitting/wear → Replace the cylinder head.
3. Measure:
• Valve seat width C "a"
Out of specification → Replace the cylinder
head.
Valve seat width C (intake)
0.90–1.10 mm (0.0354–0.0433 in)
Limit
1.6 mm (0.06 in)
Valve seat width C (exhaust)
1.10–1.30 mm (0.0433–0.0512 in)
Limit
1.8 mm (0.07 in)
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a. Apply Mechanic's blueing dye (Dykem) "b"
onto the valve face.
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