Checking The Valve Seats - Yamaha Vmax VMX17C 2009 Service Manual

Valve guide remover (ø5)
90890-04097
Valve guide remover (5.0 mm)
YM-04097
Valve guide installer (ø5)
90890-04098
Valve guide installer (5.0 mm)
YM-04098
Valve guide reamer (ø5)
90890-04099
Valve guide reamer (5.0 mm)
YM-04099
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 D "a"
Out of specification → Replace the valve.
Valve margin thickness D (intake)
1.00 mm (0.0394 in)
Valve margin thickness D (ex-
haust)
1.00 mm (0.0394 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 valve stem seal.
L LLL L L LLL L LLL
5-32
VALVES AND VALVE SPRINGS
Valve stem runout
0.010 mm (0.0004 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)
1.10–1.30 mm (0.0433–0.0512 in)
Valve seat width C (exhaust)
1.10–1.30 mm (0.0433–0.0512 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