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D
E
4
AILY
URO
Figure 180
Take out the screws (1) and remove the rear cover (2)
together with its gasket.
Figure 181
Insert a suitable pin (2) in the hole (⇒) of the chain drive (3).
Take out the screws (4) and (6) with their washers (5) for
fixing gears to the camshafts.
Take out the screws (7) and remove the chain drive (3) from
the overhead (1).
Figure 182
Turn over the overhead (1) and, taking care not to damage
the seats, extract the camshafts (2) and (3) from it.
Print 603.93.651
5412
TIMING SYSTEM
Figure 183
75469
1. Camshaft on intake side — 2. Hydraulic tightener —
3. Camshaft on exhaust side — 4. MORSE chain —
5. Rocker arms — 6. Hydraulic reacting tappet —
Description
The timing system is the type with a twin camshaft in the head
and four valves per cylinder with hydraulic tappets.
Motion is transmitted by the crankshaft, via a toothed belt,
to the gear keyed onto the intake valve drive shaft. The drive
transmission of the exhaust valve drive shaft takes place via
a MORSE-type chain kept under tension by a hydraulic
tightener.
The toothed belt, moreover, drives the water pump and the
75470
high-pressure pump CP3 and is kept at the right tension by
an automatic tightener roller.
The four valves move by the action of the "free" rocker arms
(with no supporting shaft).
The rocker arms, one per valve, are always in contact with
the corresponding cam and are kept in this position by a
hydraulic reacting tappet, thereby eliminating the need for
periodical adjustment.
Figure 184
75471
TIMING SYSTEM DIAGRAM
F1A ENGINE
7. Valve assembly.
99
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Base - March 2006
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