My XXs ground wires on the frame just behind the tank were not making good contact. Everything looked nice and clean, no corrosion, but wasn't making good contact. The bike was only a week old and the battery was going down pretty fast and the fuel gauges were fluctuating like O.J. Simpson's heart during his trial.
I called my dealer, Honda Of Laurel, Laurel Mississippi (GREAT DEALER) they told me just what to do. Remove the bolt holding the ground wires and scrape the area where the wires contact the frame, clean the wire terminals and bolt everything back down tight. Presto, it worked like a charm.
Not sure if it will help your situation but it is something simple and quick to try. There is another grounding point up in the nose of the bike, that is another place to look.
Hope it helps