Italjet Dragster 2022, Maintenance Manual

Page: 147 / 165

- Measure the sealing surface width on the valve
seats.
VALVE SEALING SURFACE
Specification Desc./Quantity
Intake valve - sealing surface (125) 2.30 +/- 0.15 mm (0.0905 +/- 0.0059 in)
Intake valve - sealing surface (200) 1.97 +/- 0.15 mm (1.0776 +/- 0.0059 in)
Exhaust valve - sealing surface (125/200) 2.95 +/- 0.15 mm (0.1161 +/- 0.0059 in)
Valve chamfering (all valves) 0.2 +/- 0.1 mm x 45° (0.0079 +/- 0.0039 in x 45°)
Inspecting the valve housings
•
Remove any carbon deposits from the valve guides.
•
Measure the inside diameter of each valve guide.
•
Measure according to the thrust direction at three different heights.
Characteristic
Intake guide - standard diameter
4.012 mm (0.1579 in)
Intake guide: Wear limit
4.020 mm (0.1582 in)
Discharge guide - standard diameter
4.012 mm (0.1579 in)
Discharge guide: Wear limit
4.020 mm (0.1582 in)
•
Replace the head if the values corre-
sponding to the width of the mark on
the valve seat or the valve guide diam-
eter exceed the specified limits.
•
Check the width of the mark on the
valve seat «V».
Characteristic
Wear limit for the width of the mark on the valve
seat "V"
•
Intake (125): 1.6 mm (0.0630 in)
•
Exhaust (125): 1.8 mm (0.0708 in)
•
Intake (200): 1.6 mm (0.0630 in)
•
Exhaust (200): 2.0 mm (0.0787 in)
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