I have a 2000 KLX that I got for next to nothing. Non running. During teardown, I discovered I will be replacing valves, cylinder, and piston.

Knowing a bit about the valve issues from research, I am just wondering what may have caused the exhaust valves to look like they do. At first I thought it was carbon build up, but wire brush and scraper could not remove it.

Thanks for any input!


EDIT TO ADD: I just realized I posted this in the wrong forum. Could a mod please move this to the tech forum?