it can be only either the float itself or float needle or float height that is the problem if i could draw you a picture of how it works i would,but basically the petrol goes in the carb via a metal tube then it goes into a round tube shaped hole a needle fits into the hole and the needle is joined to a float made of plastic that hinges on a pin so whan you turn on the petrol if flows into the carb and goes into the float bowl at the bottom as the petrol height rises the float is lifted up(as it should be floating on the top of the petrol)when it gets to the height needed it pushes the float needle into the tube shaped hole (needle seat) and stops the petrol fromflowing anymore .obviously when the fuel is used by the engine the float drops down and allows more fuel to come in and so on and so on.So the problem is either one of these 3 things .1 the float needle is not seating properly in the needle seat,can be caused by a bit of fluff or dirt or just a worn needle tip.2 the float is not floating on top of the petrol ,could have a split or crack in it.3 the float height is too low ,caused by the float needle not being pused up far enough by the float due to a bent tag where it fits onto the float...but no all floats have a metal tag some are just all made of plastic which is more than likely what your mini moto has got as they are cheaply made.i hope this helps you out i cant really help anymore than this.good luck
adam bike doctor
September 2006