Yamaha F400A 2022 - Replacing the Valve Guide

7-62
Cylinder head
2. Calculate:
• Valve stem to valve guide clearance
Out of specification → Replace the valve
and valve guide.
Replacing the valve guide
After replacing a valve guide, check the valve
seat contact area.
1. Remove:
•Valve guide “1”
(from the combustion chamber side)
2. Install:
• Valve guide “1”
(from the camshaft side)
TIP:
Make sure that the valve guide installation
height “a” is within specification.
3. Ream:
•Valve guide “1”
TIP:
• To ream the valve guide “1”, turn the valve
guide reamer “2” clockwise.
• When removing the valve guide reamer “2”,
do not turn it counterclockwise.
• After reaming the valve guide “1”, make sure
to clean it.
Inside diameter IN
5.504–5.522 mm (0.2167–
0.2174 in)
Inside diameter EX
5.504–5.522 mm (0.2167–
0.2174 in)
Valve stem to valve guide clear-
ance = valve guide inside diameter
– valve stem diameter
Clearance IN
0.012–0.045 mm (0.0005–
0.0018 in)
Limit
0.070 mm (0.0028 in)
Clearance EX
0.025–0.058 mm (0.0010–
0.0023 in)
Limit
0.080 mm (0.0032 in)
Valve guide remover/installer “2”
90890-06801
Valve guide remover “2”
YB-06801
2
1
Valve guide remover/installer “2”
90890-06801
Valve guide remover “2”
YB-06801
Installation height
11.30–11.70 mm (0.4449–
0.4606 in)
New
2
a
1
EE
2
1
EE