Is selling a motorcycle before the end of 2011—out of fear that its value would decrease in the new year—and the money earned from it, unlawful? And what must the seller do if it is unlawful?

If the buyer agrees to purchase the commodity for the agreed-upon price, then there is no blame upon you, due to His Almighty's saying: "O you who have believed, do not consume one another's wealth unjustly but only [in lawful] trade by mutual consent," and due to His (peace be upon him) saying: "Indeed, selling is by mutual consent."