Hi Don, welcome!
It's common with these bikes for the carburetors to get dirty, and it's very difficult to get them truly clean. Take a look at this page:
https://n4mwd.blogspot.com/2013/10/s...-passages.html
Did you use jets from a carb kit when you rebuilt them? If so, that is probably contributing to your trouble. Kits contain aftermarket jets that are not correct. Also, if someone previously worked on the carbs, it's possible they assembled them wrong or left out important pieces. That happened to a guy here recently.