VESPA LXV 125, Service Station Manual

Page: 132 / 226

Lack of tightness or the fact that the valve opens
at different vacuum values should be regarded as
anomalies. In this case, replace it.
N.B.
LACK OF TIGHTNESS IN THE CUT-OFF VALVE RESULTS
IN EXHAUST NOISE (EXPLOSIONS IN THE MUFFLER). IN-
CORRECT CUT-OFF VALVE CALIBRATION CAN RESULT
IN CATALYTIC CONVERTER MALFUNCTIONING
N.B.
A FAULTY CUT-OFF VALVE DIAPHRAGM, BESIDES
JEOPARDISING THE CORRECT OPERATION OF THE
CUT-OFF VALVE, ALSO DAMAGES IDLE FUNCTIONING
Specific tooling
020329Y MityVac vacuum-operated pump
Fuel supply
- Disconnect the fuel supply and the suction taking
pipe from the carburettor.
- Check that there are no fuel leaks between the
two tubes.
- Close the fuel outlet pipe.
- By means of the MITIVAC pump apply 0.1 bar of
suction to the tap.
- Make sure that the suction is kept stable and that
and that there are no fuel leaks.
- Reconnect the suction pipe to the manifold.
- Position the fuel pipe with the outlet at the point
of the tap.
- Turn the engine by using the starter for five sec-
onds with the carburettor at minimum.
- Take up the fuel by means of a graded burette.
N.B.
THE MEASUREMENT MAY BE FALSIFIED BY THE INCOR-
RECT NUMBER OF REVS OR BY THE WRONG POSITION
OF THE TUBE.. IN THIS CASE, THE TENDENCY IS TO OB-
TAIN A REDUCED FUEL FLOW RATE. THE SUCTION OUT-
Engine
LXV 125
ENG - 132