Your 500 mile trip home is probably what caused the chain to become dry. Recommended lubrication interval varies with everyone's personal opinion, but the book says 600km, so slightly less than 400 miles. (I do it every few days, without checking mileage, or on a long trip at the end of each days ride. ) You can use any brand chain lube, they all work, or simply rub down with an oily rag. Just be sure to avoid stiff brushes as they can damage the o rings.
I don't want a pickle, I just want to ride my motorsickle. A. Guthrie.