“This came from a motor with a piston that failed. There are some nicks in the combustion chamber and some melted piston too. Most if it has cleaned up, but I would suggest doing a little more hand cleaning. I would suggest hand filing the high spots from the nicks. The intake valves hold acetone, but a small amount of acetone leaks past the exhaust valves. I suspect a small piece of aluminum is trapped in the seat. The amount of leakage I saw would not concern me, and I honestly believe it'll get better with run time. Any small flake of aluminum will either melt from combustion or fall out after a few thousand valve cycles. This is a good used part unless the description says otherwise or shown in the photos. Please be sure to read the full item description and verify fitment. The title and parts compatibility list may/will have errors, they both list likely models this part may fit, but additional verification must be made to be sure it's correct for your application.”