I've got a rattle that is pretty unnerving. It's decidedly louder at low RPMs.. I notice it when I'm pulling away from stop signs if I don't rev it much, or if I get on it in a higher gear than I should be in. (like switching streets and starting off in 3rd instead of 2nd or even first). My chain isn't perfect, and a 530 on a 525 rear sprocket, but I don't think that's it... a couple of descriptions of the CCT noise fit mine well, but I haven't seen many posts about doing this to older bikes.

The bike came with an aluminum 45 tooth rear sprocket, full exhaust, and a stage 2 jet kit so it's a safe bet that it's been.. ahem, "used".

Would getting a manual tensioner be a good thing to try for getting rid of the noise, and even if it doesn't fix it, not a waste of money? The automatic tensioners go eventually anyway, right? o_O

It's not going to hurt either way to get a manual tensioner. It's a good idea for the future even if thats not what the sound is. Just my .02