Gilera 633721 Workshop Manual page 227

Nexus 500 euro 3
16 - Disconnect the pump connector, start the en-
gine, wait until it stops and connect the connector
again.
Disconnect the fuel return pipe from the pump sup-
port (left pipe).
AHEAD go to 17
17 - Introduce the return pipe into a graduated
container.
Using the diagnostic tester, start the fuel pump for
10 seconds.
Make sure that the power supply voltage is more
than 12V.
Measure the amount of fuel delivered.
Pump free flow rate = 300 - 320 cc.
YES go to 18 NO go to 19
Specific tooling
020460Y Scooter diagnosis and tester
18 - The fuel filter is not clogged.
The scooter can be used respecting the limit of 48000 km.
19 - The flow rate is less than 250 cc.
The fuel filter is dirty. Replace the pump support.
Pump electrics check
This section describes the operations to be carried out to perform electric checks on the pump.
Resistor check
Disconnect the connector from the pump support.
Using a tester, measure the pump winding resist-
ance.
Connect the tester probes to the pump support
pins as shown in the figure.
Electric characteristic
Resistance:
approx. 1.5 Ω
In case of infinite resistance, replace the pump.
Injection
INJEC - 227