PIAGGIO MSS X9 EVOLUTION 250 - Inspecting the valve housings; Inspecting the valves

Inspecting the valve housings
- Check the width of the imprint on the valve
seat«V» wear limit max. 1.6 mm.
- Remove any carbon formation from the valve
guides.
- Measure the inside diameter of each valve guide.
- Take the measurement at three different heights
in the rocker arm push direction.
- If the width of the impression on the valve seat or
the diameter of the valve guide exceed the speci-
fied limits, replace the cylinder head.
Characteristic
Valve seat wear Intake guide
limit accepted: 5.022
Valve seat wear Intake guide
Standard diameter: 5.000 ÷ 5.012 mm
Valve seat wear Exhaust guide
Accepted limit 5.022
Valve seat wear Exhaust guide
Standard diameter: 5.000 ÷ 5.012 mm
Inspecting the valves
- Measure the width of the sealing surface on the
valve seats and on the valves.
Sealing surface width: After use: Intake and ex-
haust: 1.6 mm
- If any of the sealing surfaces on the valves is
wider than the specified limit or is damaged in one
or more points, or curved, replace the valve with a
new one.
CAUTION
DO NOT REVERSE THE FITTING POSITIONS OF THE
VALVES (RIGHT - LEFT).
Characteristic
Valve wear check Standard: Intake and ex-
haust:
0.99 - 1.27 mm
- Measure the diameter of the valve stems in the three positions indicated in the diagram.
Engine MSS X9 Evolution 250
ENG - 120