Fuel puddle in rubber caps for carb sync tubes

What would cause this?

When the bike sits for more than a day, the little rubber caps that cover the air tubes (used for hooking up a vac gauge for carb balancing) get full of gasoline.

Model is a '77 KZ650B1. Are my needle/seats worn out?

It's normal to have a little gas there. Enough to pour out a few drops at least.

It's normal if the bike has been running, if the caps are getting fuel in them with the bike just sitting there not running then the float bowls are overflowing either because of improper float height or worn out needle/seat.

There's always the talk of gas making it's way into the engine from floats sticking. It's happened, more often on the newer CV carbs which I have no knowledge of, however unfortunately I've got a lot of experience with these slide carbs :X. Someone will have to explain this phenomena to me where I understand. You have 4 carbs. All 4 carbs have an overflow tube in the center. The overflow tube is between 5mm and 10mm lower than the throat of the intake into the head so theoretically as long as the tube/hose is not clogged or gas supply outruns runoff capability there is no way on this green earth gas can find it's way into the engine. The only other way would be a bad diaphram on the vacuum petcock. If it happened to leak gas between the inner and outer gas could possibly go down the vacuum line. This is rare. Now that's my personal opinion going by logic, but it still happens? I really don't get it. All I can say is over the years I don't know how many float sticking, bad needle/seat, even installed a needle upside down once. I've had puddles 8ft diameter under the bike, but yet to get gas in my oil to this day.

same engine here its normal...you can relax now