dodmo, as you have found by now eBay is all fine and dandy for spreading the word to folks who are actively looking to purchase. Your excellent listing tells the story, you've got bids.
With active bids you cannot alter certain details, and one thing I would never do is involve PayPal for the sale of valuable and complicated items, vehicles in particular. PayPal will take a fee for processing the payment, and also a disgruntled punter can work the system to get a full refund, and as such is a scammers hunting ground. Without a bid you could have removed the PayPal reference. To have put Cash on Collection only, in the listing, would also sort out the realists from the dreamers.
Insist on Cash on Collection, sold as seen, thanks and goodbye. Anyone serious will never buy unseen, so be prepared to be reasonably accommodating to arrange viewing, but don't haggle on a firm bid, that is what someone is prepared to pay on the day. If they don't like what they see in the flesh, and won't honour what they bid, fine. You will have slightly lower bids, so give the second chance offer or you can try again or elsewhere.
As an aside, the bike seems to be performing well, and as long as the oil tank level stays more or less the same after a run, it is working fine. Someone may turn up to view before the listing ends, see if you will haggle, and then you have a dilemma. Take the money, cancel the listing or let it run. This is why things on eBay are there one day and then mysteriously "no longer available."
Good luck, you should be successful.
Swarfy.