APRILIA V990 Manual page 47

V990 engine
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Carefully read 0.5.1 (PRECAUTIONS AND GENERAL
INFORMATIONS).
NOTE
The following operations can be performed with-
out removing the engine from the frame.
a
WARNING
The head must be disassembled together with the
cylinder. This is the only way in which the head can
be detached from the actual cylinder.
NOTE
If the disassembly is carried out after the remov-
al of the front cylinder, the operations marked with "
have already been carried out.
Otherwise (removal of rear cylinder only), do not carry out
the operation marked with "
N
Remove the two spark plugs of the rear cylinder (1)
from the head, see 0.4.1 (VEHICLE WORKSHOP
MANUALS).
N
Unscrew and remove the five complete spacer screws
M6 (2) and remove the head cover (3) together with the
gasket.
N
Unscrew and remove the two M10 T.C.E.I. screws (4)
and remove the support bracket (5).
N ✱
Remove the closing screw (6), made from plastic,
complete with O-ring (7) housed in the centre of the fly-
wheel cover.
N ✱
Remove the M8 T.C.E.I. screw (8) complete with
seal.
NOTE
With the driving gear (9) installed, it is NOT pos-
sible to read the reference marks "IN" (10) and "EX" (11)
on the gear wheel (12), but it is necessary to refer only to
the marks "IN" (10) and "EX" (11) on the gear wheel (13).
Do not remove the driving gear (9) in order to be able to
read the reference marks, since the removal would pre-
vent the rotation of the upper balance shaft.
a
CAUTION
✖
When turning the driving shaft, guide the connect-
ing rod and timing chain of front cylinder so as to
prevent them from getting stuck inside the housing.
N
Use a size 14 mm bent hexagon-head driver (14) to
turn the driving shaft anticlockwise so that rear piston is
at TDC (ignition).
NOTE
At the TDC (ignition), the reference marks "IN"
(10) and "EX" (11) of the two gears prove parallel to the
head uncoupling surface, and face each other.
NOTE Have the appropriate special tool m to hand:
– aprilia part# 0240880 (threaded bolt to lock the drive
shaft at the TDC) (15).
N
Screw the special tool (15) into the slot previously oc-
cupied by the M8 T.C.E.I. screw (8) by hand so that you
can feel it fit perfectly inside the driving shaft fastening
slot.
NOTE
Turn the driving shaft both ways to make sure
that the threaded bolt is engaged perfectly.
The bolt should not be overtightened.
Threaded pin driving torque: max. 5 Nm (0.5 kgm).
Release 00/2001-06
✖
".
Follow
2
2
✱
"
7
15
ã
9
DISASSEMBLING THE ENGINE
2
1
5
4
14
6
8
IN IN
10
13
11 EX EX
12
3
3
2
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