Another gas leak question

Seems to be quite a few folks asking about gas leaks. So I'll go ahead and throw mine into the mix.

Edit: Forgot the vital info- 1983 KZ1100 LTD

So while the PO took really good care of the bike, it stayed in a climate controlled room, it wasn't ridden very often. Maybe just a few miles a month to keep things running. He said that he never had any trouble with the gas leaking. Never had trouble with it myself for the first 1000 miles or so. Then it would pop up on occasion but has recently gotten much worse. The weird thing is that it mostly leaks while I'm parked at work, not at home. Both are level parking lots and it doesn't matter whether it is on the center stand or side stand.

At first I thought that it was a float problem or maybe trash in the valve seat. Today though I got off work and it was leaking way worse than I have ever seen it. I pulled the air box hoses back enough trying to see which carb it was. There was gas coming from all four. How likely is it that all four carbs have a problem? Or is it possible that I have a bad petcock? I know the needle should cut off any gas flow, but with it being all four carbs I'm just not sure.

Thanks for any help.

What model and year bike?

It is odd that all four leak, but not unheard of.
Have you checked the gas cap vent? If the bike is out in the sun at work, the tank may build up enough pressure to overcome the various valves.

More likely though, is just ordinary failure of the petcock and one or more float valves. A serious leak requires failure of both. Petcock leaks are common. The little oring deteriorates over time, dirt can get trapped in it, and the seat can oxidize. Careful cleaning, polishing the seat, and renewing the rubber bits is not difficult or expensive.
The float valves in the carbs, if they are oem or equivalent, usually just need a good clean and polish. Time consuming, but cheap.
A high quality inline fuel filter is a really good idea. Golan makes some excellent reuse able ones, and the inexpensive, cone-shaped plastic ones will do pretty well and are available at most motorcycle repair shops.

Thanks TexasKz. Hadn’t thought about the gas cap. I’ll check it over good, but either way it looks like it may be a good idea to rebuild the petcock and at least clean the floats and needle valve/seat.
Good thing I have the week off.