Taxation on Bitcoin that I owned only momentarily?

A friend of mine has offered to buy my motorcycle but he wants to pay a portion of it (about $4000) with Bitcoin. I have a bitcoin wallet and I know that If I cash some of it out I have to pay capital gains tax on it. I am wondering how it works If my friend sends me the 0.0330 bitcoin to my wallet then I immediately converted it to USD$. Since I only held it momentarily there should be no gain or just a tiny amount. Or would I be taxed on a first in first out situation, where I'm actually cashing out the bitcoin that has been in my wallet and the new bitcoin stays for later? I've told my friend that I don't want any extra tax burden, and I'm not interested in holding this bitcoin as I'm selling the motorcycle to get out from under some other debt. Any help would be appreciated.