Yamaha MIO Service Manual page 24

Item
Valve, valve seat, valve guide
Valve clearance (cold)
Valve dimensions
A
Head Diameter
"A" head diameter
"B" face width
"C" seat width
"D" margin thickness
Stem outside diameter
Guide inside diameter
Valve stem-to-guide clearance
Valve stem runout limit
ENGINE SPECIFICATIONS
IN 0.06 ~ 0.10 mm (0.0024 ~ 0.0039 in)
EX 0.08 ~ 0.12 mm (0.0031 ~ 0.0047 in)
B
Face Width
IN 22.9 ~ 23.1 mm (0.9016 ~ 0.9094 in)
EX 19.9 ~ 20.1 mm (0.7835 ~ 0.7913 in)
IN 1.20 ~ 2.50 mm (0.0472 ~ 0.0984 in)
EX 1.30 ~ 2.40 mm (0.0512 ~ 0.0945 in)
IN 0.9 ~ 1.1 mm (0.0354 ~ 0.0433 in)
EX 0.9 ~ 1.1 mm (0.0354 ~ 0.0433 in)
IN 0.7 mm (0.0276 in)
EX 1.0 mm (0.0394 in)
IN 4.970 ~ 4.985 mm (0.1957 ~ 0.1963 in)
EX 4.955 ~ 4.970 mm (0.1951 ~ 0.1957 in)
IN 5.000 ~ 5.012 mm (0.1969 ~ 0.1973 in)
EX 5.000 ~ 5.012 mm (0.1969 ~ 0.1973 in)
IN 0.015 ~ 0.042 mm (0.0006 ~ 0.0017 in)
EX 0.030 ~ 0.057 mm (0.0012 ~ 0.0022 in)
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2 - 4
Standard
C
Seat Width
SPEC
Limit
----
----
D
Margin Thickness
----
----
----
----
1.6 mm
(0.0630 in)
1.6 mm
(0.0630 in)
----
----
4.930 mm
(0.1941 in)
4.920 mm
(0.1937 in)
5.050 mm
(0.1988 in)
5.050 mm
(0.1988 in)
0.080 mm
(0.0031 in)
0.110 mm
(0.0043 in)
0.01 mm
(0.0004 in)