Vacuum hose keeps popping off.

[Crof]

97 Kat 750
OK the back story. Bike was leaking gas. Popped the tank replaced one of the gas tubes that cracked on me, the one that goes over to the right side of the bike. stopped leaking looked good. Rode to school (thank god i didn't sit in traffic for once in my life.) last 10 min of ride hit a couple red lights and bike starts cutting out. Managed to get to school by throwing the choke up when i needed to stop as when it gets down 1RPM it dies out. Between classes realized i forgot to or rather didnt know to plug in the vacuum hose.

Now, hose is in bike running fine, i take it a block, hit traffic bike stops. I pull over pop the tank and again hose is out. zip tie it, run it 2 min no choke, bike dies. Really need to make it home at this point to Brooklyn 10:30 middle of Manhattan. get some crazy glue, glue the dam hose to the nipple and double ziptie. run it a few min looks good ride home and thankfully am alive.

So i understand the crazy glue probably isnt the best fix here. Any reason why it keeps popping out that anyone can think of? there seams to be enough slack and all.
Can the vacuum be pulling it out or something?

Just to make sure the vacuum hose goes into the small nipple between the 2 gas lines yes?

any help would be very much appreciated before i start gluing my wheels and fairings on with crazy glue too =).

Also couple of stupid questions if you could.
1- do the 2 gas lines differ? does it matter which goes where?
2- the gas nob on the left of the bike. down is vacuum, which way is prime and reserve mine are not labeled.

[Black_peter]

OK so by vacuum hose you mean the one that goes to the fuel switch?
I have has issues with the vacuum caps for the synch ports popping off. I know others have too, I suspected it was a weird backfire type of event most likely during starting or shutting off the engine. So that might be your cause. For some reason the #4 carb is pressurizing and popping off the hose.

Also couple of stupid questions if you could.

1- do the 2 gas lines differ? does it matter which goes where?

Should not matter..
2- the gas nob on the left of the bike. down is vacuum, which way is prime and reserve mine are not labeled.
The "gas knob" the fuel switch or petcock..
Pointing forward is Reserve. That is the bottom 1 gallon or so of gas, as you're driving along and the fuel gets low it will sputter and die.
You switch over to reserve (hopefully before it dies) and that means you have that (small) amount of gas before you're dry.
Down is "on" this is where you leave it 99.99% of the time. The vacuum still shuts the fuel off in this and Reserve.
Pointed back is "prime" this is uncontrolled flow of gas (from the reserve level) this position is used if your carbs are dry and it can't start or produce enough vacuum to turn on the fuel in "on" or "reserve". Or of you're having vacuum issues and need to bypass the vacuum shut off.
The vacuum shut off is to protect you from overflowing the carbs if the carb valves are flaky. I suspect the adoption of vacuum petcocks is the result of a lawsuit.

[steves]

One line feeds gas to carbs 1&2, the other to carbs 3&4.

You can read about the petcock here: http://katriders.com/wiki/index.php5?title=Petcock

[Crof]

thanks whats the best way to keep the vacuum on get a special clamp for it?

[ATOMonkey]

Replace that old crusty hose.