If your bike is an SP1:
First, check for a blown fan fuse, which is fuse B in you fuse box.
If the fuse is ok, then with the engine at operating temperature, disconnect the connector from the fan motor switch and ground the connector with a jumper wire.
Turn the ignition on and check fan motor operation.
If the motor starts, then check the fan motor switch terminal. You may have to replace the fan motor switch.
If the fan motor does not start, measure the voltage between the Black/Blue and Green wire terminals at the fan motor 2P connector. There should be battery voltage.
If there is battery voltage, then replace the fan motor.
If there is not battery voltage, then check for open circuit between Black/Blue and Green wires.