Put my bike back together after a lot of work and it ran fine a few times but I didnt ride it cause I was busy spraying the fairings. Put them on got ready for a spin and she leaked fuel then died, wouldnt start. I drid off the rear spark plugs (blowtorch) and it fired easily but pissed fuel everywhere as well as out the exhaust and died again.

On inspection the leak is from the front of the bike and definitely above the carb rubbers and only leaks while running the engine. I cant tell if its coming out the over flow but it seems the most likely source.

So I assume it is the float/s but before I rip the carbs open I want to know if there is any way that by opening the carbs I will be able to tell if this was the problem. ie. I dont want to open up, fiddle around/clean, and put it back together and find I have not fixed the problem?

Side note: The carbs are very clean with no blockages, is it possible for the floats to get stuck in a recently cleaned carb without turning the bike upside down?

Floats can be stuck on re-assembly.

It'll only overflow with the engine running as the tap is vaccum operated so the fuel supply is shut off.

If you want to test the floats.

Remove the tank and use a temporary fuel tank like a pop bottle that isn't vaccum operated and the carbs should leak.

Try giving the float bowls a good few taps (no need to remove from engine) with the handle end of a long screwdriver.

This can often cure the problem if its just a stuck float.

If it's a bad float pin seal then no amount of tapping or reassembling will fix.

Some times tapping the side of the float bowl with the shaft of a hammer frees the float/needle if stuck.

When refitting carbs the needle may jam if the carbs were hit or hammered to fit them.
The float pin may not be fitted correctly, but first take off the tank to establish where the leak is, fit a funnel in the fuel pipe and fill with petrol and look around carbs.
If no leaks appear around joints or hoses but only from the overflow, then suspect float/needle in that carb.
It may free up when you remove the carbs, but before re fitting them, fill them with fuel with the funnel again to check.

Thanks guys, narrowed it down to the right overflow with your advice and turned out I had used too much sealant which was touching the floats, all sorted.