I have a 99 adventure with about 12,000 miles on it. Since I got it 4,500 miles I have been changing the oil every 1500, 2000 miles. I have not done the main bearing upgrade. Everytime I change the oil, here is about what I get on my drain plug: But what is concerning me more are the bigger particle at the base of the screen of the following picture. Any ideas where they may be coming from? Is it serious, or should I keep riding? Please, tell me it is not too serious I just pay my tuitions and that took care of any extra cash I may have had.