Most AutoZone clerks will look at you like a dog that's just been shown a card trick if you tell them you're looking for something for a 40 year old motorcycle. They're not usually much more help if you're getting parts for a car.
If you order from Z1 tonight, there's a good chance you will have it by Friday or Saturday. They ship priority mail, and usually the same day you order if you place it early enough in the day.
If you don't want to wait until then, there has to be some place in your area that has it. Some place like Tractor Supply Company, or a shop that works on old air-cooled VW's, or a lawnmower repair shop should have some.