I would contact the seller explain and offer to pay his listing fee if I really didn't want the item... or you could not pay and ebay will probably cancel your account. Apparently you like the bike or you wouldn't have bid, so just buy it.

If I was in the situation where I didn't want the item(which I don't see me bidding on something I don't want), seller demanded payment, and it was a grand.. I wouldn't pay.. the seller will be mad and have to do paperwork, but he should be refunded. 1 NPB wouldn't cancel me though, but apparently you don't use ebay anyway and by your record you don't need to.