On the subject of sellers calling me back after a sale, I bought a 750 with a ticking sound while running, "it's the exhaust gaskets, they need replacing," "Hokay" I said and did the deal.
Turns out it was a rod bearing gone bad, the ticking was too much slop in the piston/con-rod movement.
So the seller calls me a week later, I'm really surprised, he said "did you fix the trouble on the bike, I'm curious?"
"No, turned out not to be exhaust gaskets" I said, "I put in brand new gaskets and the ticking remained, it's a bad con rod bearing."
muffled laughter, "Oh - okay, well good luck." CLICK.
You take your chances when you're out there, sometimes you apparently get laughed at. Some dang sellers are mean aren't they. Most aren't.