A quick search of the part number showed 21 available at vintage that can be purchased through your harley dealer and one on eBay.
Lefty loosy, righty tighty. I don’t know what else to tell you.
Beyond that you will want to take it to a mechanic. Gasoline is flammable and very dangerous. Be sure to remove the battery cables before beginning and be sure to not do this around a spark or open flame. Do not drink the gasoline. I found those tidbits of advice in a google search also.