My 99 900RR has been making one hell of a racket lately, but it's only between about 4250 - 4400 rpm...below or above those numbers it's fine. In between those numbers though, the thing makes a teeth chattering vibration that can be felt anywhere on the bike, frame, subframe, tailpiple, clip ons...everywhere...and it's way loud.

what could be causing this? I tried tightening and torquing everything to spec, hanger bolts, exhaust header nuts...anything I could get a wrench on. I tried using a stethescope to pinpoint the noise, but everything on the bike vibrates!

I think I'm going to get an APE manual cam chain tensioner, and see if that fixes it, but from what I've read about other peoples CCT's going out, their symptoms don't sound like mine.
BTW my bike still pulls like a raped ape in every gear.

So what could it be? Give me your best guess!

 

well i had a vibration prob a while back too. turned out the rubber dampers on the side of the fuel tank fell off. the 900 is a real buzzy bike and it was vibrating the tank on the frame and making an awful racket. line the edges of the tank with some door stripping for cars. no more vibe. just my .02 good luck

 

Both black spacers are in place. had that happen before though, rattled the tank everywhere. good guess though.

could it be that I need a new cam chain? not just a tensioner? or something is wrong with the guide? or one of the cam gear? or could it be in need of a valve adjustment???

It's weird because it only happens a this one specific rev range...4250-4400rpm approximately