PIAGGIO 2005 XEVO 400ie, Workshop Manual

Page: 133 / 376

STANDARD VALVE LENGTH
Specification Desc./Quantity
Inlet: 95.0 ± 0.3 mm
Outlet: 94.2 ± 0.3 mm
- Check that there are no signs of wear on the surface of contact with the articulated register terminal.
- If no anomalies are found during the above
checks, you can use the same valves. To obtain
better sealing performance, grind the valve seats.
Grind the valves gently with a fine-grained lapping
compound. During the grinding, keep the cylinder
head with the valve axes in a horizontal position.
This will prevent the lapping compound residues
from penetrating between the valve stem and the
guide (see figure).
CAUTION
TO AVOID SCORING THE FAYING SURFACE, DO NOT KEEP ROTATING THE VALVE WHEN NO
LAPPING COMPOUND IS LEFT. CAREFULLY WASH THE CYLINDER HEAD AND THE VALVES
WITH A SUITABLE PRODUCT FOR THE TYPE OF LAPPING COMPOUND BEING USED.
CAUTION
DO NOT REVERSE THE FITTING POSITIONS OF THE VALVES (RIGHT - LEFT).
Inspecting the springs and half-cones
- Check that the upper and lower supporting spring
washers, the cotters and the oil seal show exhibit
no signs of abnormal wear. Replace a component
when worn.
XEVO 400ie
Engine
ENG - 133