After doing my valve check and cam timing, I must have failed to wipe a streak of oil below the plug for the TDC tool. The following day went riding forest roads and got the lower part of the bike covered with mud. After washing the bike the next day, the oil streak left a yellow stain. I tried to remove the streak with cleaner wax, and rubbing compound, with no success. The surface is permanently stained. I have never seen engine paint on a motorcycle stain like this. It is obviously deeper than a surface stain. Maybe it's not paint, but powder coated. All I know is it won't come off.