Slight engine rattle on higher rpms

Hey everyone.

First post here, and unfortunately it's about an issue with my bike. I have a 2002 VFR that has started giving me a slight rattle on higher rpms. I can only hear it when I engine brake (no throttle) in higher speeds (over 60kph) and it goes away if I clutch (i.e. rpms fall). It doesn't seem affected by engine temp and other then that it seems to run smoothly and all.

I've searched around a little and the main cause of rattling seems to be cam chain tensioners, but as I understand it that causes a rattle you can hear over the engine noise and someone mentioned it going away when the temperature went up to working levels.

I can't say for sure that this is a new noise or something I just haven't heard before. But it's not very loud, sounds sort of like someone is shaking a soda can with a piece of plastic or metal in it down under me somewhere (hard to locate where it comes from since it's only audible while riding) at a seemingly random interval (one to a couple of times per second).

And a few days ago my tachometer stopped working, I don't think it's related (haven't had time to check fuses yet), but I figured I should throw this in here just in case it's some known issue or something.

Thankful for any insight or help you can give.