There have been 2 types of external motors, used on the EZip-IZip.
The straight cut MY1080Z - Loud, more powerful
The helical geared XYD-16 - quiet, less power-speed
They do appear to look ... identical, have not compared closely.
Motor types
I clean the grease out and apply wheel bearing grease.
Just coat the gears teeth, then an extra marble sized gob, where the gears meet.
As an experiment, I also applied 2 balanced smears on the concave potion of the reduction gear.
My reasoning being ... If the gear were to overheat, lack of grease etc, the grease would slide outward hitting the drive gear - self lubricating.
If you remove the reduction gear, a "tension washer" might displace, make sure it is repositioned and lubed.
"Alignment" is performed by positioning the reduction gear cover, before tightening the cover screws.
Experimentation is necessary, tension towards tighter-looser gear meshing while tightening screws, try, then report!
Note: Any rear wheel work is greatly facilitated by doing the T-Plug mod.
100 amp T-Plug connector (Dean's Plug)
I was able to complete a spoke replacement in 11 minutes!