I always use Ebay, you have an absolutely massive readership.
I start off really cheeky and if it doesn't go drop it after a few weeks depending on how soon I need to sell it.
I'm always surprised how many I've sold in the past for "cheeky" money.
I've not personally found hassle from selling on there, a couple of silly offers and the odd guy questioning the price but nothing any problem.
Have you put your bike on here or our Facebook page ?
G