I have little experience with carbs, and unfortunately don't really have time to work on them or get to know them although I would really like to :/
Anyways, my girlfriend got a 91 bandit 400 last fall that was running well when we first got it and has since become a giant PITA.
It supposedly had the carbs recently cleaned, and there wasn't any issue with throttle response.
The first problem we experienced was attributed to the vacuum hose coming off, and after that was replaced the bandit had some crazy idling and revving issues. From what it sounded like, it seemed to be a vacuum leak. The idle was just wild, like anywhere from idling at 1800 to redline, and would change sporadically just as I thought I had dialed it in. Letting on a little bit of throttle would bring it way up and it would always just stay in the high rpm's for a while and slowly come back down (like 10-20 seconds).
This was in early winter and eventually it was time for storage, so we threw in some stabil and brought it to its winter resting spot. Now as the weather has been nice, we have tried multiple times to get the bandit started again but to no avail. I checked the boots for cracks and found none, and aside from the vacuum hose am not too sure what else to check for a vacuum leak. I also did the carb cleaner test and it was concluded that there was no vacuum leak (at least from there).

Anyone have any suggestions or advice for a couple of newbies who are stuck in the mud? Anyone with experience to a similar machine near Golden want to come take a look? We'd be willing to offer beer as compensation for the time

Thanks