PIAGGIO MSS Fly 50 4T Workshop Manual page 56

Electrical system
a) Bursting of protection fuse (regulator short-
circuited).
Check the wiring running from the fuse to the ig-
nition key-switch is not damaged, as this may cre-
ate a short-circuit with earth (thus excluding
possible regulator failures); if the protection fuse
bursts only after the ignition key-switch is turned
to "ON", and with the regulator connector detach-
ed, it is then necessary to check the wirings and
systems downstream the key-switch are not short-
circuited with earth.
Proceed by measuring the resistance between
contacts 3 (White) and 2 (Black) from the voltage
regulator (with the connector detached).
If the reading differs excessively from the figures
shown, replace the regulator as short-circuited.
b) Battery not recharging (regulator circuit inter-
rupted).
To check for the presence of faults on the recharg-
ing section of the voltage regulator, it is necessary
to initially operate on the battery, using two testers
(one for voltages and one for currents), as shown
in the second figure, and follow the operations giv-
en below:
Start the engine (connecting, temporarily, the red
wire to the positive terminal of the battery, so to
avoid damaging the instrument measuring the cur-
rent).
Check the voltage at idle is at least 13V (charged
battery) and the recharge current is 1.5 - 2A with
the lighting system and the choke device exclu-
ded, as described in the chapter "CHECKING THE
VOLTAGE REGULATOR".
As the engine speed increases, so do the recharge
current and voltage, and at speeds above 4,000
rpm, a recharging current of approx. 4.5A must be
observed; reactivating the lighting system and
choke device, and operating the stop light and
ELE SYS - 56
MSS Fly 50 4T