54
Fig.63
Fig.64
Fig.65
Fig.66
6.
Valve, valve spring, valve oil seal, spring seat assembly removal and
installation
：
Removal
：
Using special tools for valve compression, take out valve locking pieces, don't compress
spring excessively, compress spring enough to slip locking pieces out of its stroke, or valve stem may
be bent. If valve locking pieces do not come out during spring compression, remove compression tools,
put an appropriate pipe on spring seat
，
so the valve locking piece will not be impacted. Put a wooden
block on valve head (with cylinder head combustion chamber facing workbench), and then strike pipe
end with hammer. Reinstall special tools for valve spring compression, locking pieces may be taken out.
After locking piece is taken out, remove compression tools by unbolting slowly.
——Remove valve spring seat and valve spring
，
take out valve oil seal spring seat assembly with
screwdriver
，
and valve oil seal spring seat must be replaced.
——Overturn cylinder head
，
remove intake and exhaust valves.
——Keep each set of valve, valve locking pieces, valve spring, spring seat in the same plastic bag and
mark numbers on it, so the parts may be installed in the original place.
——Valve standard sizes and clearance
：
Unit
：
mm
Grade
Intake
valve
Exhaust valve
Valve
stem
diameter
Valve
guide hole
diameter
Clearance
Valve
stem
diameter
Valve
guide hole
diameter
Clearance
Standard
8.043+0
-0.018
8.063-8.094
0.02-0.069
8.017+0
-0.018
8.063-8.094
0.046-0.095
Oversize0.4
8.443+0
-0.018
8.463-8.494
8.417+0
-0.018
8.463-8.494
