Shibaura SG280E, Руководство по ремонту

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21
5) Inspect and check valves.
Inspect the heads and stems of valves, and replace
those with significant damage, wear, or deformation.
Use a micrometer to measure valve stems at
positions A, B, and C, and replace those that fall
below the usage limit.
Valve stem wear (mm)
Intake valve Exhaust valve
Assembly
standard
Usage
limit
Assembly
standard
Usage
limit
6.955 to
6.970
6.89
or less
6.940 to
6.955
6.84
or less
Valves with heads whose thickness exceeds the
usage limit should be replaced.
Valve head thickness (mm)
Assembly standard Usage limit
0.925 to 1.075 0.5 or less
If the clearance between the valve and valve guide
exceeds the usage limit, replace the valve.
Clearance between valve and valve guide (mm)
Intake valve Exhaust valve
Assembly
standard
Usage
limit
Assembly
standard
Usage
limit
0.03 to
0.06
0.20
or more
0.040 to
0.065
0.25
or more
Use 15 degree, 45 degree, and 75 degree seat
cutters to repair the seat so that the width and
recess are within the assembly standard.
Valve seat contact width (mm)
Assembly standard Usage limit
1.2 to 1.8 2.5 or more
Valve seat recess (mm)
Assembly standard Usage limit
0.6 to 1.2 1.8 or more
Fig.2-5-6
Fig.2-5-7
Fig.2-5-5
Fig.2-5-9
Fig.2-5-8