Hi all, this is my first post here, but I've been lurking for a while.I've gotten alot of good info from reading posts here and I'm hoping to get some guidance on an issue I discovered today while changing my oil.I recently purchased a used 1999 DR350SEX with 20,000 miles on it. The bike starts well both cold and hot. It does not smoke, and seems to run very well in general. Today I did an oil and filter change and when I pulled my strainer, I found that there are some metal shavings in it. I did not have the forethought to take a picture but they were pretty big (aprx 16th of an inch wide, 8th- 1/4 inch long). I looked closely at the filter and it did not appear to have any metal in it. The previous owner told me he had recently changed the oil, when I changed it, it looked normal as far as color goes for used oil.My question is, where should I start looking to find the cause of this problem? I've done some significant engine work to car engines (older V8's) with the help of friends and my first thought was a bearing in the bottom end, but from what I've read these bikes tend to have issues with the valvetrain around 20k miles, so I'm wondering if I should start looking there.Thanks in advance for any advice.