Montesa COTA 4RT 260 2023, Owner'S Manual

Page: 89 / 180

Engine servicing
4-26 4-26
Valve/Valve Guide
Inspect each valve for out-of-round, burns, scratches or
abnormal stem wear.
Check the valve movement in the guide.
Measure and record the valve stem O.D.
Service limits:
IN: 4.470 mm (0.1760 in)
EX: 4.460 mm (0.1756 in)
(1) VALVE
Valve spring
Check the valve springs for fatigue or damage.
Measure the free length of the intake and exhaust valve
springs.
Service limits:
Inner: 24.9 mm (0.98 in)
Outer: 27.6 mm (1.09 in)
(1) OUTER VALVE SPRING
(2) INNER VALVE SPRING
Cylinder Head Inspection
Cylinder Head
Remove the carbon deposits from the combustion
chamber or exhaust port.
Use care not to scratch the combustion chamber or the
head gasket surface.
Check the spark plug hole and valve area for cranks.
Check the cylinder head for warpage with a straight edge
and feeler gauge.
Service limit: 0.05 mm (0.002 in)
(1) COMBUSTION CHAMBER
1
1
1 2