Does anyone recognize this gunk? I've seen it both times at the last two changes after going to Mobil 4T Racing 10W40.
It feels like moly grease, smears with no perceptible grittiness at all, and cleans up with a brushstroke with some kerosene. There is no other junk in the filter except a tiny amount of small flakes and sometimes a whisker.
The engine is running fine. I'm thinking it could be from the oil carbonizing during the occasional high temp/low speed trail section.