A few weekends ago I was at the track with my 06 Yamaha R6 and I began to lose power coming out of a corner, followed by what I would describe as a clicking noise, almost like a playing card lodged in a bicycle rim. I got off the track no more than 10 seconds after hearing the noise and killed the ignition.
Tried to start it again back at the pit but wouldn't start. Engine now sounded more like a knock and also kind of a grinding noise or like there was friction impeding the piston or something.
Opened up the air box and no excess oil or grenaded parts. Manually cranked it over at the stator and felt compression strokes. Brought it home, opened up the oil pan and found pic related.
I was originally thinking spun bearing but seeing this spiral and crimped up pattern seems to suggest a large piece of metal got chewed up by the gears. There is also what looks like thread locker in the oil pump screen/net.
Had a friend mentioned there are thrust washers between the gears and it's possible one of them failed, but it's a guess until I open it up.
Anyone seen this before?