18
6
Cylinder head and valves
Notice in maintenance Disassembly of cylinder head Inspection for valve seat
Troubleshooting Break down cylinder head Inspection for valves
Disassembly for cylinder head cover Inspect valve and its guide tube Repair valve seat
Remove bracket of cam Inspect cylinder head Assemble cylinder head
Remove camshaft Inspect valve springs Install cylinder head
Inspect camshaft Replace guiding tube of valves
Install camshaft
Notice in maintenance
Summary
Engine must be disassembled when camshaft, cylinder head, and valve tappet rod is in
maintenance, and spread lubricant on camshaft and tappet rod when assembly is needed
for basic lubrication.
Size and specification for each part
Items
Standard data
（
mm
）
Limits
（
mm
）
Camshaft
Height of air intake cam
36.20
～
36.30
36.10
Height of air exhaust cam
36.17
～
36.27
36.07
Diameter of camshaft
22.967
～
22.980
22.94
Diameter of hole of camshaft
bracket
23.000
～
23.021
23.08
Clearance
between
camshaft and bracket
0.020
～
0.054
0.15
Valves
Width of line of air intake
valve
0.7
0.45
Width of line of air exhaust
valve
0.8
0.5
Diameter of rod of air intake
valve
4.475
～
4.49
4.460
Diameter of rod of air
exhaust valve
4.455
～
4.470
4.440
Pore size of guiding tube of
air intake valve
4.510
～
4.522
4.59
Pore size of guiding tube of
air exhaust valve
4.510
～
4.522
4.59
Clearance
between
air
intake valve and guide rod
0.02
～
0.047
0.07
Clearance
between
air
exhaust valve and guide rod
0.04
～
0.067
0.08
Plate diameter of air intake
valve
28.9
～
29.1
/
Plate of diameter of air
exhaust valve
24.9
～
25.1
/
Clearance of
valves
Air intake valve
0.10
～
0.19
/
Air exhaust valve
0.15
～
0.24
/
Valve springs
Height of inner spring under
free condition
36.2
34.5
Height of outer spring under
free condition
41.1
39.4
Length of chain
（
20 links
）
127.0
～
127.4
138.9