Yamaha SR400 2014 Service Manual page 192

2. Replace:
• Valve guide
TIP
To ease valve guide removal and installation,
and to maintain the correct fit, heat the cylinder
head to 100 C (212 F) in an oven.
▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼
a. Remove the valve guide with the valve guide
remover "1".
b. Install the new valve guides with the valve
guide installer "2" and valve guide remover
"1".
VALVES AND VALVE SPRINGS
c. After installing the valve guide, bore the valve
guide with the valve guide reamer "3" to ob-
tain the proper valve-stem-to-valve-guide
clearance.
TIP
After replacing the valve guide, reface the valve
seat.
Valve guide remover & installer
set (ø8.0)
90890-04014
Valve guide remover (8.0 mm)
YM-01200
Valve guide reamer (8.0 mm)
YM-01211
▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲
3. Eliminate:
• Carbon deposits
(from the valve face and valve seat)
4. Check:
• Valve stem end
Mushroom shape or diameter larger than the
body of the valve stem  Replace the valve.
5. 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.
Valve stem runout
0.030 mm (0.0012 in)
5-18