bdas2, why do I get the feeling you are thinking about hauling a big pile of heavy stuff and want others to tell you it will be alright?

When it comes to safety, I think it is fairly wise to err on the side of caution. If the manufacturer of the vehicle says the load limit is X, he has usually put a small extra safety factor in the calculations. But that safety factor probably doesn't equate to a real load limit of 2X, or 3X, or 4X. The same is likely true for things like tires, GVWR for cars, trucks, and motorcycles, ladders (one with a 150 lb load limit probably wouldn't be the best choice for a 350 lb NFL lineman), etc.
If you must overload, keep the excess weight as low and as far forward as you can. It's much better to put the heavy stuff in the bottom of the saddlebags, and the light stuff in the TP. And of course adjust your riding to suit your overloaded condition.
Jerry