J.mcculloch said:Has anyone carried a 500+ pound bike for long periods of time on the back of a van in a carrier?
I have a friend who has carried a Kawasaki KLR650 on a hitch rack for many thousands of miles on the back of a Chevy Pickup. He has occasionally carried a Honda VFR 1200 and although that is a heavy bike, it has been successful so far. And I would recommend the best carrier you can find, not the cheapest. And a hitch tightener. And heavy duty straps!
For any bike above ~300 lbs or so, I prefer a trailer.
There is a class of trailer called the 'swivel wheel' trailer that might be an option...but they are NOT cheap:
http://www.discountramps.com/swivel-wheel-trailer/p/SW-58/
Swivel wheels in action:
(short video)
(long video)