I've learned my lesson with purchasing vehicles on TR and or any other internet source. This comes down to, you as a buyer, need to take precautions when purchasing or trading for a vehicle. Don't rush into it, take your time, if the seller's legit, I don't think they would have a problem for you to take the car and get it checked out. If they hesitate, it would automatically tell me to stay away, that they would most likely have something to hide.

I've gotten fucked recently, but besides posting up a thread, legally, there wasn't much I could have done. Pretty much the same thing in your case, even though the seller was a piece of shit, but you should have also taken a closer look.

At my shop, we charge $70 for a front to back, top to bottom, side to side check of the entire vehicle. I believe a lot of other mechanic shops will also do the same for a fee, spend the money, get it looked at, it would, at very least, give you a piece of mind.

Now, have you considered that he didn't know of the problems the bike may have had? That might have been the case, I would think if he was trying to pull a quick one, that he would have not called you and bitched about the injectors and then finally trading back with you.