First post here, thanks for having me. I searched for a question like this but didn't see anything like this posted in my searches for combinations or 'oil' or 'rebuild' or 'black', so I apologize if this is a repost of something that's been asked before. I picked up a used '06 450 and I've been riding the bike for three weekends. It has great power compared to my '05 KTM SX 250 2 stroke. I'm really happy with the YZ's performance. The thing pulls my arms out of the sockets. However, the oil has a black 'glitter' suspended in it and I would like opinions on what it might be. It's like there is metal flake material from a candy coat paint job mixed into my oil. I have never seen anything like this before. I thought it was cluth material as the clutch was slipping some on the first ride. I replaced it and no more clutch slip, but I still have all this glittery metal flake in my oil. The flakey stuff streaks up a bit and kind of 'clouds' up in the oil and is opaque, but the oil around the flakes looks clear like fresh oil. The previous owner told me he replaced the crank bearing before selling and did a top end on it, yet it's smoking slightly at high rev's. Am I seeing material in the oil from the top end bedding in? Do I just ride it untill winter and keep changing oil every ride and do a top end this winter or dive in now and replace the top end ASAP before riding any more?