Anyone know where it should connect to?
All the Workshop manual says is disconnect the vacuum hose...but from where?
Mine is connected to the fuel pressure regulator on the side of the tank fuel pump gubbins, but it wasn't connected to any vacuum.
On earlier bikes, it connected to a little spigot on the underside of the airbox. Later bikes it wasn't connected to anything (hangs loose) and the airbox spigot was no longer there. Many bikes don't even have the hose.
If your airbox has the spigot, stick a self tapper in it and leave the hose loose.