Bandit 400 Help

[SisuBrewing]

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

[Wrider]

Did you check the balance of the carbs? I've found bandits to be pretty picky on that. I owned a 400 myself for a short time, they're pretty awesome bikes. Hard to come by.

[asp_125]

You're in Golden? If you give up on it, take it to Jim at TFOG. He'll set you right.

[SisuBrewing]

The carbs seemed well balanced right when we got it, and that lasted a few weeks. Then in a period of about a day or two (when we figured out the vacuum hose had disconnected) everything turned sour and just has not been the same, so am i wrong to assume that it wasn't the balance of the carbs?

Thanks for the heads up about TFOG! The easiest route seems like the best route for us right now, although I really wish I had the time to clean or rebuild the carbs..

[Nolan]

+1 on TFOG... Took a bank of carbs from an 86 gsxr and aside from parts was under $100 to rebuild and once I put them back on I dropped the bike off to be synced for another hour of labor. Starts flawlessly....

[Spooph]

yea, if you're not particularly comfortable with carbs I wouldn't mess with it. TFOG can straighten you out.

I say this from plenty of experience hunting down issues with carbs and it's a long list of things to go through. If it were me, I would remove the carbs and rebuild them simply to inspect them and make sure everything is good.

The long time to come back down to idle sounds like an air leak as that's typical extreme-lean behavior, so somewhere, way too much air is getting into the carbs.

[Wrider]

I have a bank of carbs sitting on my bookshelf at the moment. They're either from the Bandit 400 or an early Ninja 600. Are yours Keihin CVKs with the throttle adjustment on the left side of the bike? If so you're welcome to these ones.

[Jim_Vess]

I had similar symptoms a few years ago on a 1981 Yamaha Seca 550. It turned out to be the butterfly shaft (some call them throttle shaft) seals were leaking. If that's the case and you're not comfortable taking the carb bank apart, let someone else do it. It can be done (I did mine) but it's a time-consuming. PITA task.