PIAGGIO ZIP 4T - Inspecting the Valve Sealings; Inspecting the Valve Housings

Inspecting the valve sealings
- Insert the valves into the cylinder head.
- Test the 2 valves alternatively.
- The test is carried out by filling the manifold with
petrol and checking that the head does not ooze
through the valves when these are just pressed
with the fingers.
- Measure the width of the sealing surface on the
valve seats.
Characteristic
Sealing surface width: Intake
1.5 mm
Sealing surface width: Drainage
1.6 mm
Inspecting the valve housings
- 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.
Characteristic
Discharge guide: Standard diameter
5 +0+0.012mm
Discharge guide: Wear limit
5.022 mm
Intake guide: Standard diameter
5 +0+0.012mm
Intake guide: Wear limit
5.022 mm
- If the width of the impression on the valve seat or the diameter of the valve guide exceed the specified
limits, replace the cylinder head.
- Check width of the impression on the valve seat «V»
Characteristic
MSS ZIP 100 4T Engine
ENG - 99