The newspapers and
http://www.cycletrader.com would be your best bet.
I think ebay would be a bad idea. 1st thing, if you seperated it for parts it would take you months if not years to sell all those parts for an uncommon motorcycle.
2nd, if you do put it on ebay, you will have people wanting you to ship it, which would probably be more trouble than it's worth ( especially at a $500 price tag)
All else fails, I would hold on to it. You never know if you want to get back into a hobby. I sold a classic car at a major loss and have regretted it ever since.