Dr Dwight, that is a great post - by doing the carb tear down and fixing the problem in one pass you clearly identified the issue.
Its too common of an issue, primarily caused by 10% ( E10) fuel breaking down after sitting for a few months. And that makes it worse for motorcycles because they tend to be seasonal vehicles, and you are never sure when your last ride of the season will be. By the time you realize you have not taken a ride since september and now its December, the fuel has already degraded, and you cannot fix or stabilize fuel that has already gone bad.
There is a simple prevention: keep a bottle of any fuel stabilizer in your garage, and as soon as you realize you might not ride again for a month or more, put the proper amount in your tank. If someone only rides once a month, they should be putting a stabilizer in every tank of gas. If you only use half a tank a month, fill it up, use half a tank, then 1/4 of your tank is two months old.
This happens so often to so many riders that people think motorcycle carbs must be torn down and cleaned on a regular basis. That is not true - if the fuel is well maintained and stabilized over winter, and a bike is not parked for years without being touched, it should never be necessary to clean a carb by hand.
This was never an issue until they started with the 10% ethanol gasoline. 100% gasoline will get old and lose some of its energy/gallon, but it never use to turn into goop in our tanks and carbs.