The starter/generator bearings don't usually need a thick pre-lube as they are not exposed to a lot of high heat or extreme torque on intial start-up; and a thick lube will get spun/thrown off into the inerds and may gunk up the brushes. 3-in-1 electric fan/motor oil is A-OK perfect.

The above advice for the 3-in-1 motor oils is what I have used on electric motors for many years and had a 100% success, even with the bronze oillight bearings.

I have found that the starter/generators are a little "tight" after a pro-rebuild and thus a couple of drops of 3-in-1 frequently applied will extend the life of your start/gen a lot. Mine seem to use more oil till they get a good break-in. Oil them 3to4 drops frequently and they seem to last forever: IF ya keep them clean of dirt build-up.

Finally, use Never-Seize and a torque wrench when installing starters/generator bolts and you'll be glad ya did when it comes time to adjust the fan belt or remove the starter!