Echos right, I would say running wise its probably the carbs. I have to clean carbs on every bike I get. Im also thinking you might have some crap in the tank. Drain the tank, look inside of it, if need be wash it out till its completely clean with water (without the petcock on the tank) and let it air dry and blow it dry with compressed air. Make sure the petcock is clean and reinstall then fill her back up with gas. Run an inline fuel filter, and if the petcock is vacuum operated make sure all of the vacuum lines running from the tank to the carbs/carbholders are clean and clear.