You will need the "by 10" key (a socket head is more convenient).
1. Disconnect the wire from the negative terminal of the battery.
2. Remove the air filter (see "Removing and installing the air filter"), since its air intake pipe prevents the electric fan from being removed.
3. Disconnect the wiring harness connector from the electric fan.
4. Unscrew the two bolts securing the electric fan casing on the left, unscrew the two nuts on top...
5. …the nut from below…
6. ...and remove the electric fan assembly with the casing.
7. Install the electric fan and all removed parts in the reverse order of removal.