cadunkle,
What you have there are shavings from your block and head. Your cam chain is loose and it is eating away at the aluminum. I had the same exact thing happen to my bike when I bought it. The PO never adjusted the cam chain tensioner correctly. I drained the oil, adjusted the cam chain properly, installed a new oil filter and filled the bike with clean oil. I ran the bike for 1000 miles and drained the oil. The metal was gone. No worries.
Sparty