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Inspection and Maintenance
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Valve-seat tightness check
With the valve and spring properly fitted, pour a
small amount of petrol through the intake- or
exhaust port.
Check to see that no petrol is leaking through the
valve seat. If a leak is found, tighten the sealing
surface.
WARNING
Petrol is highly inflammable and explosive. Keep
the petrol away from heat sources, sparks or flames.
Valve-spring
The strength of the helical spring keeps the valve-
seat pressed. A weak spring will result in loss of
engine power and valve-mechanism clattering.
Check the strength of the valve springs by
measuring their unsupported length and the
amount of strength required to compress them.
If the unsupported length of a spring is found to
be below the service limit, or if the strength required
to compress it is not within the specified value,
replace the inner and outer springs altogether.
DETAILS
Spring unsupported length (intake and exhaust)
Service limit:
Inner: 32.6 mm
Outer: 36.3 mm
DETAILS
Valve-spring tension (intake and exhaust)
Normal:
Inner: 5.6-6.4 kgf/27.4 mm
Outer: 12.6-14.5 kgf/30.9 mm
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