Air box flapper doesn't close.
I read about the air box flapper, it said it kicks in at a specific RPM. I looked to see and mine was still hooked up, I jumped the bike, revved it up and it never closed.
I checked the hose and it doesn't seem to have any vacuum. When is the flapper supposed to be closed?
I didn't check to see if the hose was connected way up under the tank, but I'll get to that someday.
Where does the hose get it's vacuum from, intake runner or air filter box?
I know it doesn't need to be closed, and there's a popular mod to keep it open, I'm just wondering why it doesn't work. Might indicate a problem, even a vacuum leak if it fell off.
My guess is that it's based on vacuum from an intake runner and under high vacuum it'll close?