2002 YZF250, Last night I changed my oil and found the oil filter completely covered with some black material(very fine particles). It looks like it is soft like rubber or plastic, maybe even dirt. The only thing I could think of is the cam chain slider, maybe it is getting chewed up. The oil has about 12 hours riding on it, Oil is 10W40 (bought from a reputable bike shop) Has anyone else had this problem..... Please Help!