Don't really know how it works down there in the States, as I'm writing from Canada (first post ever here too! Sweeeet), but can't the new buyer just make the certified cheque out to both you and your bank's / title holder's name? That way the cheque MUST be used to pay off the loan, the loan clears, there is no lien anymore, and your Bill of Sale would be sufficient to get him on his way to register it, no?
Failing that, my Dad used an escrow agency to buy his 1967 Royal Enfield from across the country. Dad put money in Escrow, Seller retains ownership until Conditions are met (in Dad's case, just a simple look over of the bike to make sure it was as advertised), then when conditions were cleared, funds were released from Escrow to seller.
Don't know if either of those help! Wish I was ready to pull the trigger on my new bike...yours caught my eye hence why I'm here reading your thread. :) Nice bike man...hope it nets you what you need out of it.