Okay, here's a shot in the dark. I looked at the parts diagrams on Partzilla for the 1990 Yamaha XVZVenture and the part number for Carb#3 is 1NL-14903-02-00,
The 1990 VMax Carb #3 is 2WF-14903-02-00. If the first three characters are only model designators, you might have an alternate source...