Gilera Nexus 500, Workshop Manual, Page: 225 / 406

side, can be easily removed. Once clean, the throttle body guarantees an air flow exactly the same as
the original. Throttle valve fouling is phenomenon that happens at different times depending on how
the scooter is used, weather conditions and idle speed adjustment. This phenomenon can be easily
detected as a gradual poor idle signals it. Carry out a thorough check with a scooter diagnostic tester,
drw. 020460y. With engine temperature of at least 90°, the parameters may be as follows:
Standard Dirty throttle body
Engine revs 1500±5 < 1400
Ignition advance 5°÷7° 10°
Throttle valve opening 5.24° 5.24°
The error menu displays the signals stored in the "RPM sensor". This takes place only when the engine
stops with the key switch set to "on." An exhaust fumes analysis will show a very rich and non adjustable
idle carburetion (CO > 4% - CO2 < 12%). Measure with the tool in drw. 020625y. It is evident that,
except for cases of early fouling, cleaning should not be carried out when still covered by the warranty.
After cleaning the throttle body, check and, if necessary, adjust C0. If these indications occur when the
injection warning light turns on or further errors or wrong parameters are present, it is necessary to carry
out the relevant controls indicated in the manual. In such a case, there is a real fault evidently.
Refitting the butterfly valve
- Carry out the operations in the reverse order of
the disassembly, tighten the 3 set screws to the
prescribed torque.
Locking torques (N*m)
Throttle body fixing screws 11 ÷ 13
Pump supply circuit
The control unit starts the pump in the following conditions:
- by setting the switch to " ON " with emergency switch to " RUN " and side stand raised. The pump does
not supply.
- If the phase rotation signal is received. Continuous supply.
The initial timing is useful to bleed the system especially after a stop with engine in temperature. In
these conditions, the fuel altered by boiling will be mixed with that in the tank.
During use, the pump operation will be subject to the engine speed.
Nexus 500
Injection
INJEC - 33