Carrying a Motorcycle with my 2000 Shasta Sprite?

Don’t do it. The Dana 70 rear axle on your E350 is only rated for a weight of 8500 lbs I believe. If your Class-C is 25’ or longer, you are probably near or over that weight limit already with your tanks full and other added items in your rear storage compartments. Check your rear axle weight at a truck scale. Adding 500 lbs to your rear hitch will (depending on your wheel base) will probably add 750 lbs weight to your rear axle and delete 250 lbs from your front axle.