Hello Steve,
I have the same machine, also a '73, just a golden color.
Last year I overhauled the carburetor and got all the parts from a Honda Bike Dealer. However, about a week later the place closed down and I said man were do I get the parts from when I need some. They told me the reason for closing was that now the Honda car dealers can also sell & service bikes.
Thats the story from the Canadian side, might be different in the US, but it's worth a try I would say, good luck.
Eddie