If the drain screws are closed all the way, it is likely that your float needles are gummed up and not closing. If the float needle does not close, gas will flood your carb and drain out the overflow. have your carbs cleaned, or do it yourself if your brave. Its not that hard if you stay organized ang get a manual. Also, those drain hoses should be longe enough to empty below the bike. you dont want gas pouring onto your hot engine.