A lot might remember I had serious carb
puke. Very serious. off and on, I did it all. Lines, cover them, re route, new float valve, ditch the pump, on and on. Never really cured it although I thought I did a few times.
Now, Once I ditched the Leaky Ben Herr Manifold that was leaking on and off whenever it wanted and could not be stopped for three years. The problem was solved. Never puked since I installed the Factory Manifold with the hylomar sealant.
Why? I am thinking because the bike was on and off running very lean with the intake leaks. This made it run hot enough to boil the gas in the bowl.
Mind you I could tune it all in with jetting, but as the bike went down the road it would start to leak and lean out, sometimes it would and sometimes it would not. With the sealed intake, it runs right and the same ALL The time. And so far not one puke and a very cool bowl from shut down to cold.
So, I seriously suggest investigating a running lean situation.
And this may be why some people complain about it and some don't.
Let the flaming begin.