The bushing is oilite bronze, which really doesn't need lube, but if you want to go traditional, put a piece of cotton sash cord into the opening under the oil cup and drip just a little SAE 30 oil into it. The oldtime generator rebuilding kits included new oil wicks, along with bushings and other small parts necessary to do a good rebuilding job.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!