Yanmar 1GM User Manual page 83

SINGLE-CYLINDER ENGINES
H---l
1"!I---2
~1G...t--3
~--4
~-5
6
!-7
77
VALVE COMPONENTS
1. Wear cap
2. Keys
3. Valve spring retainer
4. Valve spring
5. Valve seal
6. Valve guide
7. Valve
VALVES AND VALVE SEATS
Servicing the valves, guides and valve seats must be
done by a dealer or machine shop, as special knowledge
and expensive machine tools are required.
A general practice among those who do their own ser-
vice is to remove the cylinder head, perform all disassem-
bly except valve removal and take the head to a dealer or
machine shop for inspection and service. Since the cost is
low relative to the required effort and equipment, this is
usually the best approach, even for experienced mechan-
ics. The following procedures are provided to acquaint the
home mechanic with the procedure.
Valve Removal
Refer to Figure 22.
1. Remove the cylinder head as described in this chapter.
2. Remove the rocker shaft assembly as described in this
chapter.
3. Remove the wear cap (1, Figure 22) on the valve stem.
4. Compress the valve spring with a compressor like the
one shown in Figure 23.