Setting the preload. This didn't work as well as I'd hoped as the runout on the plate was much greater than the axial movement I was trying to measure. I think the indicator mounting needed to be more rigid too.
There are no ventilation holes or channels in the motor, and no holes in the radial direction on the cover, so I think this fan is purely cosmetic. The lathe designers may have thought so too, as another fan is mounted on the sheet metal cover, aimed at the motor.
The first projects once the lathe is working must surely be pullers, drifts, punches, and so on to make taking it apart easier. I later found that the pulley had two set screws in the same hole, and I'd only removed one assuming it to be the only one there. Once the second screw was removed the pulley could be re-fitted quite easily.
One downside of removing the pulley using the motor mounting plate.