VESPA 664787, Service Station Manual

Page: 31 / 179

Checking the spark advance
-Check to be made at over 4000 rpm with strobo-
scopic gun. The advanced ignition measured must
be 17° before the TDC.
- This value is correct when the reference mark on
the flywheel hood is aligned with the reference
mark on the cooling fan and the phase shifter on
the stroboscopic gun is set on 17°.
N.B.
IN CASE OF MALFUNCTION, CARRY OUT THE CHECKS
PROVIDED FOR IN THE ELECTRICAL SYSTEM CHAPTER.
CAUTION
BEFORE CARRYING OUT THE ABOVE CHECKS, CHECK
THE CORRECT KEYING OF THE FLYWHEEL ON THE
CRANKSHAFT.
Specific tooling
020330Y Stroboscopic light to check timing
Spark plug
Place the vehicle on its central stand
- Remove the central cover, indicated in the figure,
by undoing the 2 fixing screws;
- Disconnect the spark plug HV wire cap;
-Undo the spark plug using the socket wrench;
-Examine the condition of the spark plug, check
that the insulating material is whole and measure
the distance between the electrodes using a thick-
ness gauge.
-Adjust the distance if necessary by bending the
side electrode very carefully.
In the case of defects, replace the spark plug with
one of the specified type;
- Engage the spark plug with the due inclination
and screw it right down by hand, then do it up with
the wrench at the prescribed torque;
-Fit the cap on the sparking plug as far as it will go;
- Refit the central flap.
Vespa S 50 2T
Maintenance
MAIN - 31