Yamaha F400A 2022 - Checking the Valve; Checking the Valve Guide

Cylinder head
7-61
Checking the valve
1. Check:
•Valve face
Pitted/worn → Replace.
2. Measure:
• Margin thickness “a”
Out of specification → Replace.
3. Measure:
• Stem diameter “a”
Out of specification → Replace.
4. Measure:
• Stem runout
Above specification → Replace.
Checking the valve guide
Before checking the valve guides, make sure
that the valve stem diameter is within specifi-
cation.
1. Measure:
• Inside diameter “a”
Out of specification → Replace.
Tilt limit IN
1.7 mm (0.07 in)
Tilt limit EX
1.7 mm (0.07 in)
Margin thickness IN
0.50–0.90 mm (0.0197–0.0354
in)
Margin thickness EX
0.90–1.30 mm (0.0354–0.0512
in)
a
a
Diameter IN
5.477–5.492 mm (0.2156–
0.2162 in)
Limit
5.447 mm (0.2144 in)
Diameter EX
5.464–5.479 mm (0.2151–
0.2157 in)
Limit
5.434 mm (0.2139 in)
Runout limit IN
0.01 mm (0.0004 in)
Runout limit EX
0.01 mm (0.0004 in)
a