I have a 78 kz650 and one of the carbs is leaking from the overflow hoses. I'm new to mechanic, but assume there's too much gas in the float bowl. My question is this. If the drain hose is located on the bottom of the carb and there's supposed to be gas in the carb at all times, you 'd think it would always drain, refill, then drain.

In a nutshell how do I fix this. Is it something a fairly handy guy can do, or should I take it to a mechanic and get hosed.

Your carb has a float issue I would suspect. Check the float for it having gas inside it making it heavy. Remove float and shake rapidly next to ear, if you hear liquid, float is bad.