APRILIA V990 Manual page 46

DISASSEMBLING THE ENGINE
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Follow
a
WARNING
Be careful to avoid possible injury caused by allow-
ing hands to get trapped between the cylinder and
the stud bolts (24).
N
Remove the cylinder (25) together with the complete
head (26).
a
CAUTION
When removing the cylinder, take care not to damage
the cylinder.
Be careful to keep the two locating dowels (27) from
dropping inside the crankcase.
NOTE
See 4.24 (HEAD AND CAMSHAFT) for instruc-
tions on taking the complete head apart.
N
Cover the opening in the base with a clean cloth.
N
Remove the cylinder base gasket from its slot and pull
out the two locating dowels (27).
a
CAUTION
Do not apply any mechanical markings.
N
Use a felt pen to mark the piston crown and the cylinder
on the exhaust side (28), in order to be able to reas-
semble it in the correct direction.
In the same way, mark both the piston and the cylinder
with a "1" so that the two components can be recon-
nected in the same point.
a
CAUTION
In order to prevent unbalanced forces, the axis of the
pistons' gudgeon pin is positioned off-centre, to-
wards the front of the vehicle.
When reassembling, the piston must be positioned
on the connecting rod facing the right way.
N
Using a sharp-point screwdriver (29), extract the right
and left stop rings (30) (pin locking).
N
Use a special drift to push out the gudgeon pin (31).
a
CAUTION
Hold the piston in one hand so that the connecting
rod bush is not tilted and hence damaged.
N
Remove the piston (32).
30
29
3 - 10
- 00
26
"1"
32
31
30
27
29
31
V990 engine
25
24
27
28
"1" "1" "1" "1"
32
Release 00/2001-06