It is fairly typical for bikes, even big ones like Gold Wings, to be rated for about 330 pounds total. That includes rider, passenger, and all cargo. Some are rated for max GVWR (Gross Vehicle Weight Rating) instead, which means you subtract the wet weight of the bike from GVWR and the difference is what you can carry. You might consider honestly looking at your and your passenger's weights and see how much leeway you really have. Be aware that tires also have maximum weight ratings, and one of the most common things found at bike rallies is overloaded and underinflated tires.