Gilera Nexus 500, Workshop Manual, Page: 335 / 406

- Check that the water pump cover is not damaged
or deformed.
- Check that the sealing O-Ring is in good condi-
tion
- Carefully position a new O-Ring, avoiding contact with grease or oil.
CAUTION
FAILURE TO OBSERVE THIS ADVICE CAN IRRETRIEVABLY DEFORM THE O-RING.
- Refit the water pump cover, tightening the 6 fixing
screws to the prescribed torque.
Locking torques (N*m)
Water pump cover screws 3 ÷ 4
Water pump ceramic seal
Our Leader, Quasar, and Master liquid cooled engines are equipped with water pumps fitted with the
ceramic seal in the subject. This component is intended to guarantee the leak tightness of the coolant
in relation to the pump shaft. The seal achieved via two special ceramics, a static one and a spinning
one, kept in contact by the thrust of a spring, coaxially mounted onto the pump shaft. The efficiency of
this system is guaranteed by the accurate machining and cleaning of the components as they are fitted;
in any case, ceramic seals are subjected to a running in period. During this period (1,000 ± 1,500 km),
there may be small leaks through draining holes, which remain visible on the aluminium crankcase.
This phenomenon is particularly visible there where the hole is more exposed (Quasar and Master). In
such cases we recommend cleaning the casing in order to be able to check again for leaks after a
distance of more than 1500 km. If leaks continue or in the event of real losses, the ceramic seal should
be replaced. For these operations, observe the tools and instructions given in the relevant service
station manuals.
Note: The ceramic seal may be overhauled according to the following couplings:
•
Coupling "A": seal ring no. 485084 with ceramic seal no. 486216
•
Coupling "B": seal ring no. 841329 with ceramic seal no. 841330
The couplings above may be selected according to their availability, as they are interchangeable.
Nexus 500
Cooling system
COOL SYS - 7