Checking The Valve Seats - Yamaha 2009 XP500Y TMAX Service Manual

Valve guide remover (ø4)
90890-04111
Valve guide remover (4.0 mm)
YM-04111
Valve guide installer (ø4)
90890-04112
Valve guide installer (4.0 mm)
YM-04112
Valve guide reamer (ø4)
90890-04113
Valve guide reamer (4.0 mm)
YM-04113
L LLL L LLL L L LLL L L LLL L
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 "a"
Out of specification → Replace the valve.
Valve margin thickness D (intake)
0.60–0.80 mm (0.0236–0.0315 in)
Valve margin thickness D (ex-
haust)
0.60–0.80 mm (0.0236–0.0315 in)
6. Measure:
• Valve stem runout
Out of specification → Replace the valve.
TIP
• When installing a new valve, always replace
the valve guide.
• If the valve is removed or replaced, always re-
place the oil seal.
L LLL L L LLL L LLL
5-21
VALVES AND VALVE SPRINGS
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 "a"
Out of specification → Replace the cylinder
head.
Valve seat width C (intake)
0.90–1.10 mm (0.0354–0.0433 in)
Valve seat width C (exhaust)
0.90–1.10 mm (0.0354–0.0433 in)
M MMM M MMM M M MMM M M MMM
a. Apply Mechanic's blueing dye (Dykem) "b"
onto the valve face.
M M MMM M M MMM M MMM