I took my head cover off my '07 YZ450F to check the valves and timing and noticed the cam chain guide was missing. The two pins under the head cover to hold the guide in place has wear on them from the chain rubbing them. The cam chain feels tight and the bike runs and starts fine with no problems other than the lack of bottom and mid power, which is the way the bike has been since I bought it 2 months ago. This low power is why I was checking the timing. I usually change my oil every 2 hours on my hour meter and noticed on my last oil change that there was a few chunks of very small pieces of rubber in the drained oil. So, what should I do and what should I be worried about if I can't flush all the rubber pieces out? Any advice would be greatly appreciated.