APRILIA V990 Manual page 41

V990 engine
3.1.10 SPECIAL MARKS ON THE ENGINE
For disassembly, reassembly and replacement purposes,
some parts of the engine are marked with coloured
points, letters or reference marks.
The table indicates the part (seat and element), the type
of mark, the mark function and the reference to the man-
ual chapter or paragraph.
Component
Housing
Engine crankcase (in- Main bushes (installed
side both crankcase on the engine crank-
halves). case).
Connecting rod (with no Connecting rod bush-
mark). es.
Support bushes (in-
Clutch cover (with no
stalled on the clutch
mark).
cover).
Valve seats (on the
Valve springs.
head) (with no mark).
Front head (with no
Front cylinder.
mark).
Rear head (with no
Rear cylinder.
mark).
Original front piston in-
Front cylinder.
stalled.
Original rear piston in-
Rear cylinder.
stalled.
Front cylinder marked New replacement front
with letter "A" or "B". piston.
Rear cylinder marked New replacement rear
with letter "A" or "B". piston.
Release 00/2001-06
Mark (type)
Element
Colour:
Red (minimum diame-
ter group).
Blue (medium diameter
group).
Yellow (maximum di-
ameter group).
Colour:
Red (minimum thick-
ness).
Blue (medium thick-
ness).
Yellow (maximum
thickness).
Colour:
Red (minimum diame-
ter group).
Blue (medium diameter
group).
Yellow (maximum di-
ameter group).
Not provided.
To be made on the up-
per part of the springs
upon disassembly.
Letter "A" or "B"
stamped on the lower
side of the front cylin-
der.
Letter "A" or "B"
stamped on the lower
side of the rear cylinder.
Not provided.The pis-
ton and the front cylin-
der must be marked
with number "1" upon
disassembly.
Not provided.
The piston and the rear
cylinder must be
marked with number "2"
upon disassembly.
Colour:
Red (group "A").
Green (group "B").
Colour:
Red (group "A").
Green (group "B").
DISASSEMBLING THE ENGINE
Mark function Reference to the text
Reference to the diam-
4.4 (DRIVE SHAFT
eters of the bush seats
MAIN BUSHES AND
(drive shaft and bal-
BALANCE SHAFT
ance shaft) on the
MAIN BUSHES) under
crankcase halves, for
INSTALLING THE
the choice of the size
BUSHES.
group.
4.12 (REPLACING
Reference to the thick-
AND INSTALLING
ness of the connecting
THE CONNECTING
rod bush.
RODS).
Reference to the diam-
eters of the bush seats
(drive shaft and bal-
4.21 (SUPPORT
ance shaft) on the
BUSHES).
clutch cover, for the
choice of the size
group.
4.25 (DISASSEM-
BLING THE INTAKE
Reference to the upper AND EXHAUST
part of the springs, in- VALVES).
dispensable for the cor- 4.30 (VALVES) under
rect reassembly. ASSEMBLING THE
VALVES IN THE
HEAD.
4.31 (CYLINDERS)
Reference to the "size
4.32 (PISTONS AND
group" of the front cylin-
GUDGEON PINS).
der.
5.11 (ASSEMBLING
THE PISTON AND
REAR CYLINDER).
Reference to the "size
5.17 (ASSEMBLING
group" of the rear cylin-
THE PISTON AND
der.
FRONT CYLINDER).
Reference to the cylin-
der-piston assembly 3.4 (DISASSEMBLING
and to the position of FRONT CYLINDER,
the piston in the front HEAD AND PISTON).
cylinder.
Reference to the cylin-
der-piston assembly 3.5 (DISASSEMBLING
and to the position of REAR CYLINDER,
the piston in the rear HEAD AND PISTON).
cylinder.
Reference to the front
cylinder "size group" 4.32 (PISTONS AND
("A" or "B") and to the GUDGEON PINS).
direction of assembly.
Reference to the rear
cylinder "size group" 4.32 (PISTONS AND
("A" or "B") and to the GUDGEON PINS).
direction of assembly.
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