^ after looking at the manual a bit, I dont think there is a vacuum system or diagram, its not like the bike has a vaccum assist brake booster or a PCV or vacuum advance.
I think there is only the cap on the vacuum test port on the intake side of the carb, that you would use to attach a vacuum gauge set for balancing the carbs.
If the AIS system has been disabled and now the bike is not running well, there might be a hose or plug that is leaking air - lots of people remove it completely to make the engine look cleaner, but you have to fully plug off all the ports.
the other possibility is you have a vacuum leak, which you can usually locate by pointing an un-lit propane torch at the intake boots, manifold, carb connection to the air intake box... if the idling engine speeds up you are pointing the propane flow at a vacuum leak.
you said the boot was replaced, maybe the seals are not right, or the boot is on backwards.
Last edited by KCW; 06-04-2019 at 07:25 PM.