for those that think paypal is secure be sure they send the money as a Gift if not PayPal has become more on the buyers side than the seller and as said before if paid with a credit card it can and will be reversed and you are stuck with trying to get the bike back if it has not already been striped and parted out.
If its an advanced scam ring even postal money orders can be faked and it takes several weeks for banks to figure it out and when they do the funds are pulled from your account so you are out the bike shipping and the cash.
My rule of thumb is if they have been on the board here a while I would not have a problem with paypal or money order. If it was via creigs list face to face with cash lol.
good luck with the sale