Very interesting indeed Coil, thanks for posting that. Wow Nov 1983 and Yamaha is worried about bikes in the showroom with flaking rust accumulating in the gas tanks. I wonder if it was caused by using sub grade steel. That is probably the reason today we struggle so much with badly rusted tanks. It brings to mind when GM and others used sub grade steel in the body panels in the early 70's. I had a 1973 El Camino that had 6" high rust through by 1975.
Another thing I thought interesting was replacing the main jets with similarly sized replacements because they are more precise than the originals.
I realize these bulletins are for all Yamaha models and not just our Vision, but I have a query regarding the mixture screws. The exploded view shows an O ring between the washer and spring. I have now pulled apart 4 mixture screws and have never seen an O ring. Should there be one?