The components of the timing system function with low-pressure oil lubrication.
The camshaft bearings are installed directly on the aluminium of the head; the camshaft axial clearance
is partially compensated by the oil supplied to the smaller diameter bearing.
The camshaft supplies the lubricant to the rocking levers via the holes provided; these are installed in
a position to ensure that the lubrication is maintained even after the scooter has stopped. This is ach-
ieved when the camshaft reaches its most usual and likely position when the engine is shut off.
The oil used to lubricate the head returns to the sump via the chain casing channel and therefore it also
provides lubrication for the chain.
A one-way valve and a decantation chamber are used so that gases from the crankcase do not carry
any oil. The one-way valve is a metal reed valve; the decantation chamber has a drainage hole. A failure
in these components implies oil getting into the line supplying air to the engine.
Excessive oil vapours may result in clogged ducts on the throttle body.
In order to signal low oil pressure in the system, a pressure switch is used, located immediately after
the oil filter outlet.
The lubrication circuit does not include the piston or the pin, also in this case the cooling nozzle is
particularly important.
Diagnosis guide
1 - Minimum oil pressure warning light on with hot engine.
AHEAD - go to 2
2 - Remove the minimum pressure switch electric connector.
Check that the warning light turns off.
YES - go to 3 NO go to 11
3 Check the actual oil pressure.
AHEAD - go to 4
4 - Remove the switch and fit the special tool with the relevant gasket.
Specific tooling
020193Y Oil pressure gauge
020434Y Oil pressure control fitting
- Remove the dipstick with the oil filling cap and insert a cap fitted with the temperature probe supplied
with the special tool. Insert the probe to feel contact with the crankcase bottom and pull back a few
millimetres.
Specific tooling
020331Y Digital multimeter
Engine GP 800 i.e.
ENG - 84
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