If it is coming out of the carb it sounds like you float level is too high or it is stuck open. try adjusting the level first. i had the same problem on my RMX and I just droped the level and it is fine now
canyncarvr had it right that if your float level is per spec, these things tend to dribble if not level. If I park mine on the sidestand on level ground, no gas comes out, but if the kickstand is on a downhill slope, it will leak. There seems to be a certain lean-angle after which the gas will start to dribble out.