Yamaha WaveRunner FX140 Manuel D'entretien page 358

POWR
VALVES AND VALVE SPRINGS
4. Measure:
• Valve stem diameter a
Out of specification → Replace the
valve.
Valve stem diameter a:
Intake valve:
3.975–3.990 mm
(0.1565–0.1571 in)
Exhaust valve:
4.460–4.475 mm
(0.1756–0.1762 in)
5. Measure:
• Valve stem runout
Out of specification → Replace the
valve.
NOTE:
• When installing a new valve, always replace
the valve guide.
• If the valve is removed or replaced, always
replace the oil seal.
Valve stem runout:
0.01 mm (0.0004 in)
Valve guide inspection
NOTE:
Before checking the valve guide make sure
that the valve stem diameter is within specifi-
cation.
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