Gas out of overflow tubes

OK members, here goes. I have a 1981 KZ750 Ltd H2. It has under 10,000 miles but has not been running for some years. I changed oil and filter, spark plugs, air filter, and installed a new battery. When I cranked it over it would not start, and noticed a pool of gas under the bike. It was coming out of the air box. When I pulled the overflow tubes gas continued out. I also noticed that when I changed the oil it seemed to have gas mixed with it. Any advice on a fix? Should I buy a carb kit? Should I buy another used set of carbs? Thanks for your time. Greg

Have you checked the compression or adjusted the valves? Without compression, the bike won't start. If it doesn't start, gas needs to go somewhere... have you checked for spark? Same deal. if there is no spark, the gas has to go somewhere. I would leave the carbs alone till you have the other things sorted out.

If you have the means to check the compression then absolutely do so. It is a pressure guage that threads into the spark plug port.

There are more things you could check though;

Have you looked at the plugs? Are they gas fouled?

What is the condition of the spark? Is there any spark?

It is entirely possible that there was sediment and perhaps even water in the gas tank that accumulated during the time it had not been run. This sinking sediment could have come down into the carbs and fouled the float valves (causing the overflow) acting like a foot in the door, not allowing the door/valve to close thereby shutting off the gas.

I would guess that your engine could be flooded.

If the bike has been sitting for a few years then the carbs are probably gummed up inside with the stuff left over after gas evaporates. They could probably stand a good cleaning. If you do a search you will find lots of info on cleaning carbs (not rocket science). Do you have a manual ?
If not try here kz.mbsween.com/
If gas is overflowing then its possible that the float needles are not seating. When cleaning the carbs dip a Q tip cotton swab in carb cleaner and run it around the needle seat - the brass part which the float nedle fits into.

How's your gas tank ? Any rust or corrosion. Bits of rust or other debris making their way into the carbs wil also block the float needles from seating correctly. A fuel filter will help.

I would'nt invest in new carbs just yet. Carb cleaner and a couple of screwdrivers may be all you need....maybe a bit of patience also

Thanks to all who responded to my post. I am sure this will help to get my 750 running. G