c. After installing the valve guide, expand the
hole in the valve guide with the valve guide
reamer "3" to obtain the proper valve-stem-
to-valve-guide clearance.
TIP
After replacing the valve guide, reface the valve
seat.
Valve guide remover & installer
set (ø5.5)
90890-04016
Valve guide remover (5.5 mm)
YM-01122
Valve guide installer (5.5 mm)
YM-04015
Valve guide reamer (5.5 mm)
YM-01196
▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲
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 (intake)
1.20 mm (0.0472 in)
Valve margin thickness (exhaust)
0.85 mm (0.0335 in)
VALVES AND VALVE SPRINGS
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.
Valve stem runout
0.010 mm (0.0004 in)
CHECKING THE VALVE SEATS
EASB111221
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 contact width "a"
Out of specification Replace the cylinder
head.
Valve seat contact width (intake)
0.90–1.10 mm (0.0354–0.0433 in)
Valve seat contact width (ex-
haust)
0.90–1.10 mm (0.0354–0.0433 in)
5-28