125 leaking fuel from float bowl.

Take the carb apart & while you are at it blow through the pilot & mainjet. Pull the (brass) floatjet out, removing the floatpin, float & float-needle first. Chances are the needle is worn but maybe there is some garbage behind the jet so you have to take it out. If you find garbage empty the tank & clean any filters.

Use your brain when tapping anything on a carb & support the pillars etc before you tap.

Check to see the float doesn’t leak (shake & listen).
Don’t get too hung up on levels, bend the tag & try. You can test it with your finger & the fuel line reconnected & light pressure.

If the needle is worn & you are too tight to buy a new one ;) you could try the following. Carefully drill the jet a bit bigger so the needle seats further up on an un-worn section. Don’t blame me if you mess this up, remember drill from inside. The hole will need to be redressed so drop a small ball bearing down the jet hole & tap it with a punch. This by itself may help. With a bigger hole the float tag will need to be bent up a bit to compensate for the jet having to be higher to seal the hole