On my 08WR450, I have a loud rattle that starts at about 9K RPM in second gear. its metal on metal sound. Sounds like a big washer resonating on a loose bolt. A resonating washer is a real good description of the sound. Kind of odd to be able to hear it over my exhaust.. And the sound is non-existent under 9K. I only noticed it after installing my leo vince slip on. And that might be because I rev the bike out more with the new exhaust. Or it could be internal to the pipe. But, I’m thinking it sounds like a loose motor mount bolt. Which, I messed with not to long ago to change my needle clip position in the carb. The bike as 60 hours on it. last valve check was 20 hours ago(they were adjusted). Oil and air filter get changed often. I don’t have regular intervals but I don’t go over 4 rides without an oil change. But I’m averaging 6 hours per oil change(its had 10 oil changes in its life span). My question: Any known noisemakers?. Carburetor slide vibrating? Kick stand? Kick starter? Or just should I just start tightening everything. Seams silly, but Piston hitting valves??? Is my engine going to explode or is something going to fall off the bike?