Carbs puking out the overflow??

Finally got my '82 KZ750 motor running yesterday.Still a couple of issues first is when I set the petcock to prime it just dumps fuel out of the overflow tubes and does the same when running what is the cause of this?This on a set of Mikuni BS34's

Overflow tubes on a BS34 assembly? Here is a BS34 assembly. Where is the fuel overflowing from?

Out of the over flow tubes between the #1&2 ans between the #3&4 carbs it was also coming out of the #1 carb.

Those would be vents NOT over flow tubes. Gas fills the carb bowl then there is no place for it to go. It crawls up the vent passageway and out the vent fitting. It is also in your engine oil and air cleaners if you have one installed. I would consider fixing the problem and changing the oil before starting the bike.

Reasons for overflow? Floats are stuck with gummed gas? Float levels wrong? Crud in gas getting between the float needle and seat? Float needles missing? Could be lots of things. First remove the carbs and blow out the bowls and set the fuel level using the service fuel level method. You might want to pick up some float needle/seat assemblies and install them if you don't know how to spot worn components.

I think it was the float needle seats causing the problem cleaned them up and it stopped.Thanks for the help.