If it were me, i would get his email address and send him the invoice through paypal. That way you will be covered by paypal's system. If he doesn't have a paypal account, you will see that when you send the invoice. I think paypal has a new policy now that they hold the funds for 21 days. This allows the buyer to change their mind or file a chargeback on you. If this happens, he will have the bike and get his money back too!!
Paypal is on the side of the buyer right now so please be careful! I wouldn't release the bike until that time period has expired. I would read up on paypal's policies about this before selling something that expensive.
Go with your gut...it's usually right!
