Repairing regulators is an iffy proposition! Those cutout relay points will stick if they're the least bit rough, and they usually take out the generator in the process. I'd pitch it! I've been tinkering with 6-volt DC charging systems for about 40 years, and even before the days of throwaway parts, very few people could repair and calibrate a regulator properly. The family shop back in the 50's sort of specialized in electrical repair, and we'd usually replace a regulator unless it was a high-dollar commercial unit.
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!