Gilera Runner Purejet 2007, Workshop Manual, Page: 173 / 257

to the shunt, just before the pump. The shunt is attached to the bleed tube leading to the upper-half of
the tank. The principle of communicating reservoirs guarantees the bleeding of the pump intake right
from the first refill. The pump must not be started before the tank has been filled. Failure to comply with
this rule may result in seizure of the pump. The fuel pump is installed at an angle so to improve the
efficiency of the automatic intake bleeding. Downstream of the pump is the circuit designed to operate
under pressure. The connection between the pump and the injector mounting consists of a preformed
plastic hose provided with quick-fit fittings. Before removing-attaching the fittings, follow the operations
described in "ENGINE FROM THE VEHICLE" chapter. Failure to comply with these rules may result in
the failure of the fuel injector or risk of fire to the vehicle. The circuit under pressure includes the fuel
injector and pressure regulator seals. The regulator has the aim of keeping the fuel injection pressure
constant at 2.5 BAR (250 kPa). As the fuel injector injects compressed air into the chamber, the real
fuel pressure is due to the air temperature plus 2.5 BAR (250 kPa), e.g. For example:
AIR PRESSURE = 5.5 BAR
FUEL PRESSURE = 8 BAR
When the system is working efficiently, the fuel quantity injected is only a function of the variations in
ignition timing. The supply circuit continues through the return duct from the injector mounting to the
tank. The attachment to the injector mounting is always of the quick-fit type. As this section of the circuit
is downstream the pressure regulator, it will constantly be at ambient pressure. The fittings to the injector
mounting are identified by the following markings:
FI = INLET
FO = OUTLET
The circuit provides continuous fuel flow with the tank to guarantee the uninterrupted cooling and ven-
tilation of the injector mounting and, therefore, a more constant fuel preparation. When refilling the
system after maintenance or repair operations, 10 - 11 pump cycles are required to bleed the entire
circuit. During normal use, before start-up, it is advisable to use the initial timing. To guarantee the
reliability of the fuel supply system's components, suggestions given for the fuel filter should be ob-
served. Using a vehicle with a dirty fuel filter may damage the fuel pump as a result of the bleed duct
remaining empty and, therefore, allowing the intake of air.
1. Attach the interface wiring. Omit the ECU attachment.
GO TO point 2
Specific tooling
020481Y Control unit interface wiring
2. Attach the air pressure control kit.
GO TO point 3
N.B.
TOOL INSTALLATION RESULTS IN CANCELLATION OF THE INTAKE AIR PRESSURE. DURING
THE SUBSEQUENT INSPECTIONS, RUN THE STARTER ONLY WHEN EXPLICITLY STATED IN
THE PROCEDURE.
Specific tooling
Runner Purejet
pure jet injection
INJ PJ - 173