I bought mine through a second hand dealer who was simply acting as an agent for the private owner, i.e. the dealer advertised the bike and had it in a showroom but didn't own the bike. When I agreed to buy it he contacted the owner who turned up with the log book. We went to a bank together and paid the transfer of ownership fee. We then went to the vehicle centre together and he dealt with the official there. All I had to do was produce my passport, residence permit and my AFM. I gave him the cash, he gave me the log book in my name and I collected the bike. All very simple. In theory you can pay the fee at the vehicle centre but you have to use a machine and it often doesn't work so it is easier to pay at a bank first. Alternatively, as Jean said, KEP will do it all for you but again both seller and buyer will need to go to KEP together so no big advantage. I did that both selling a car and buying another, both private transactions.