No, do not pay him through PayPal. Instead, send an e-mail through eBay telling him that you are ready, willing and able to make payment, and ask him for a firm commitment, in writing, that he will honor your contract. Give him a time certain by which to reply - 24 hours seems reasonable - and say that if he fails to reply by that time, you will take all appropriate measures under eBay rules and the law (don't specify what they are). If, and only, he writes back that he will honor his contract, then, go get the bikes in person - preferably with a witness - and pay him face-to-face when, and only when he has wheeled the bikes out to you.

The other possible alternative, assuming you have this bozo's address, is just go there with payment in hand and give him the same message, except that his time to accept is about 24 seconds instead of 24 hours. Definitely bring someone along as a witness. Also, bring along a copy of the e-mail corrrespondence in case the anus cookie calls the cops. (If he does that - and I kind of doubt he will - be very calm and reasonable in dealing with them, explain to them why you are there, show thenm your paper work - they won't resolve it for you and will likely ask you to leave, but taking that tone will insure that they treat you with respect and not like some sort of stalker.)

In any event, this guy has demonstrated that he is a rip-off artist. Do not under any circumstances give him any money unless you have the bikes in hand.