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Page 231
1. Troubleshooting
2. Maintenance Instructions
3. Removal of the cylinder head cover
4. Disassembly of the cylinder head
5. Decomposition of the cylinder head
6. Inspection of valve and valve spring
7. Rocker arm inspection
8. Inspection of cylinder head
9. Assembly of cylinder head
10. Installation of cylinder head
11. Installation of cylinder head cover
Troubleshooting
Maintenance notice
Maintenance parameters of each component
project
Standard value mm
Maintenance limit
mm
Axial clearance between rocker arm and cylinder head
rocker arm
0.05
~
0.3
0.5
Radial clearance between rocker arm and rocker arm
shaft
0.016
~
0.045
0.08
valve spring free length
Outside: 39.6 Inside:
37.7
Outside: 39.75 Inside:
36.85
valve clearance
0.06
~
0.08
------
Camshaft base circle runout
0.02
0.04
Low cylinder pressure:
1
、
valve
Incorrect valve clearance adjustment
Poor valve seal
Incorrect gas timing
Broken valve spring
2
、
cylinder head
The spark plug is not tightly connected to the
cylinder head
Damaged cylinder head gasket
Cracks or blisters in the cylinder head
3
、
Cylinders, Pistons, Piston Rings
Excessive or broken piston ring clearance
Cylinder block
Exhaust with black smoke
1
、
valve guide wear
2
、
Oil shield leaking or damaged
3
、
Cylinder head gasket leakage
4
、
Excessive piston ring clearance
Heat engine noise is too loud or abnormal
1
、
Incorrect valve adjustment
2
、
Stuck valve or broken valve spring
3
、
Excessive wear on the upper rocker arm
4
、
Incorrect gas timing
5. Camshaft wear
6. The pressure relief valve is broken
project
Standard value mm
Maintenance limit
mm
valve
valve
stem
outer
diameter
intake
φ
4.972
~φ
4.987
φ
4.96
exhaust
φ
4.96
~φ
4.975
φ
4.94
Valve
guide
inner
diameter
intake
φ
5.005
~φ
5.015
φ
5.035
exhaust
φ
5.005
~φ
5.015
φ
5.035
Valve stem and guide
clearance
intake
0.018
~
0.043
0.07
exhaust
0.35
~
0.055
0.08
valve seal width
1.5
----
cylinder head
Flatness
0.04
0.05
Valve seat working face width
0.8
----