I don't think so, although this is happening to me now too. However, my carbeurators were filfthy, so I dis-assembled them and cleaned everything really really well and I hope it stops leaking gas everywhere.
The reason I dont think this is normal is because my bike never did it before, just after sitting outside for about a year :(
Fuel running through the drain tube while the bike is upright, or on the kick stand, is usually an indication of carb floats that are out of spec. Check the FAQ for more info.
If your bike isn't on pretty much level ground when you have it on the kickstand, fuel will leak out of the float bowl. This is normal for the KDX. You don't notice this on a MX bike because there is no kickstand to lean them over on. My best advice is to cut off your fuel petcock when you plan to park your bike for a while on an uneven surface. If it's leaking out on leven ground then you float may be out of adjustment or stuck.
Mine has been doing that lately too. It doesn't do it all the time though. After a really rough rocky section it may do it. I just turn the petcock to off when I stop.
My kdx is doing that too??? And let me tell you gas is to expensive to be leaking all over the ground, at a buck a litre for 94 octane, and 17 bucks a litre for oil, it adds up :(
Sometimes a speck of dirt will get between the float valve seat and cause that problem! A quick fix is to turn off the fuel petcock and drain the carb bowl at the bottom, you don't even need to take the carb off the bike.Turn the fuel petcock on and allow a little gas to wash out the bowl. Re install the plug and turn on the fuel petcock.
Draining the bowl allows the float valve to completely open and when you let some fuel run through it, it washes the grit out of the float valve seat.
Just brought my 03 200 home and it had crud in it. This fixed mine.