1989 Vulcan 750 running problem (sort of)

I am saying it’s a possibility you need to eliminate issues one at a time . If it’s an air leak you can test for that need to see if carb boots are leaking on intake side or air side surge tank has hoses attached to it . What is the history of bike I did not read your issue from beginning did bike just start doing this there are others that will make suggestions

I’ve had this happen when the bike is really hot, sometimes the only way I can settle it down is to feather in the clutch a couple times. My bike definitely acts different depending on the weather.
I’ve never pulled my carbs but I suspected something gets a little sticky when temps get really hot. When it happens my idle just stays hung up close to 3K, when my carb boot was loose one time the idle was erratic. What is your bike doing? Is it hanging or jumping up and down?

It could be the air cut off switch works when it’s cold and works wrong
when hot. I had same symptoms