Leaky tank when fuel line is removed

[kylebach14]

So this'll be the 2nd time taking my carbs off. The first time I took them off (cleaning) my tank leaked all half gallon of gas out onto the block and when I set it on the ground. I was under the impression that it shouldnt leak at all because they are vacuum acuated. This time Im taking my carbs off to put a stage 3 jet kit in and while everything is off, I wanted to know if I need to rebuild my petcock or if this is normal. 2002 Bandit 1200. Thanks

[ventYl]

go with rebuild. B12 petcock should be repairable thus it is cheap and quick, rebuild sets should be available somewhere around 40 euros. i've had similar situation; if tank was off then here and there petcock leaked several drips when tank was moved. it ended up with engine full of fuel several times and completely new petcock (as B4 petcock is not repairable).

[chevsuz12]

A simple fix may be to pull it apart and stretch the spring slightly then put it back together.  This will create more tension against the diaphragm and will likely stop the leak.  Otherwise, a kit will be necessary.

[Rainrider]

Just went through this on my 2003 1200s.
Agree that you might very well get away with stretching the spring a bit but putting a full kit in it is easy and cheap. Dellboys garage has a great video on the procedure.

[ventYl]

by stretching the spring you'll fool yourself that you fixed it. changing spring lenght by either compressing or stretching it will cause the spring to be operated beyond it's design parameters by using force which will cause non-flexible deformation.

weakened spring is beyond it's lifespan, by further stretching it you'll add another structural damage and weaken it even faster. so it will weaken even more and lose "regained" strength far more faster than before stretching.

[Rainrider]

Once you've got the tank off and drained, makes no sense to take a shortcut for the price of a kit.