If the fan fails to work, connect a fully-charged 12 volt battery directly to the fan motor; for safety's
sake this must only be done while the fan assembly is still attached to the radiator (on or off the machine) so that it is
still enclosed by its protective shroud. If the fan motor works, the fault is in the thermostatic switch or in the main wiring
loom; check for faults as described in Chapter 10 - Electrical.
If the fan motor does not work, it must be renewed. Remove the shroud mounting bolts or screws and
withdraw the fan from the radiator.
If the fan ever comes on with the engine still cold, this is probably due to a poor earth connection
between the engine and the frame. Clean the engine/frame bellhousing mounting point as described in
Chapter 1, Section 36 - Refitting the engine unit to the frame,
also the frame earth point behind the steering head. Both must be cleaned back until metal-to-metal contact is restored to
ensure a good earth; apply a thin coat of silicone grease to prevent corrosion and tighten the mounting bolts securely