Kx 125 1998/ 99 fuel leaking out from carb overflow where floats are, when kicked up sems to be ok , but when i cut the engine it starts to leak out util i turn the fuel off, i checked to see if the floats were sticking and they seem to be ok, any help much appreciated

recheck and clean /adjust floats pet **** doesnt stop fuel in bowl if floats out of adjustment or valve sticking/debris will allow fuel to constant flow

Probably carbs overlowing, overflow pipes from the carburettor-s will hang out from below the engine, thus if the float valve sticks in the carb the fuel will overflow away from hot exhaust, you will have to follow pipe up to the offending carb remove float bowl and inspect and clean float valve, you will have to remove float and inspect the valve and its seating for dirt or varnishing which is caused when fuel is left for a prolonged time within the carb

Black smoke indicates that your mixture is way too rich. Now, you didn't say what carb you're running, stock or aftermarket. But, what it sounds like to me is the needle and seat in the carb is leaking fuel and overfilling the float bowl. When you're running down the road, you'll using enough fuel so that the float bowl does not overfill. When idling, you don't use as much fuel, the bowl overfills, and fuel flows into the carb creating a very rich mixture. Is you overflow hose that connects to the bottom of the float bowl connected, clear and open? If so, turn the petcock on without the engine running. If the overflow is clear and the needle valve is leaking, you should see fuel start to flow out of the overflow hose. This is very important that it do this. If the overflow hose is blocked and you forget to turn your petcock off, you could wind up with a couple of gallons of fuel in your engine. It will leak out of the float bowl, into the carb past the intake valves, past the rings and into the engine. I've also seen it get into the primary drive case as well. I'd put a new needle in the carb and check the float setting according to the book. it's sets with the carb on an angle if the carb is the original Keihin CV.

Good Luck
Steve

Two possibilities; the float bowl gasket is leaking, or the carburetor is overflowing (gasoline is coming out of the overflow tube).
If coming from the float bowl gasket, simply remove the float bowl and replace the gasket.
If it is overflowing remove the float bowl, pull out the float hinge pin, remove float and float valve. Clean the valve and inspect the valve for excess wear (a noticeable groove worn into the tapered seat) and replace if needed. While you have the float out, shake it and listen for any gasoline that may have leaked inside it. If there's liquid inside the float, toss it and buy a new one (or else your carb will overflow with gasoline constantly). Before you put the float bowl back on be sure to clean it out with soapy water and an old tooth brush.
That should take care of any leaks or overflowing.

sounds like the needle and seat may be the problem

your float is stuck take carburator off and clean wiggle float and it shouldnt leak gas anymore

The overflow tube coming out behind the swingarm? If that is where it is coming from sounds like your float in one of the carbs could be stuck.

not sure of the exact height, but if you hold the carb level with fuel hose attached and pushing float up with finger, turn on petcok and slowly lower the float until it is just above horizontal. at this point, gas should start to flow out of the needle & seat.

if float turns off gas too soon, then engine will starve.

if float doesn't turn off gas, then it will flow out of the carb overflow tube.