You rode the bike a little hard didn't you? Didn't you!!! Sorry I couldn't resist. Actually mine does the same thing when I park it after a spirited ride like first and second gear till 100000 rpm except mine is coolant and that is pretty normal until the coolant levels off to a just below the overflow line. It looks like the same hose now you might have gotten some road grime on your finger and that's why the coolant looks like dirty oil. As long as it doesn't keep dripping. I'm sure someone will chime in and either agree or set us both straight.