If you open the throttle via the throttle grip or the thumb screw you are allowing more air in the engine. If all is good the carb will respond by adding an appropriate amount of fuel. Then all is well. What if the carb can not add more fuel because of a low float level or plugged circuits in the carb. The engine starves for fuel and gets so lean it just dies???????the main reason I say I'm going to put it back is when I opened them a little more it wouldn't even idle anymore without me restricting the airflow on top of the bowls
I thought I was dealing with a lean condition not I'm not so sure it was even off at all
I have to figure out why when I try to raise the throttle with the thumb screw to get it to idle at 750 to 800 it will die instead of raise the idle. I never really picked up on it until now with the air filter out
before it would raise the idle but it also made the throttle down very slow, I mean slow as in let off throttle then wait, wait, wait now shift but if I kept it right at or just under 750 it was fine
I can crank my 97 up and all it does is idle high, I did that when I was first teaching my wife how to ride, that way she didn't struggle with taking off until she got the hang of it, then I turned it back down
To answer your next question, if you goose it the accelerator pump will richen the mixture and the engine could well be good enough to respond. If you accelerate s-l-o-w-l-y the accelerator pump does not pump fuel.