So i was riding my bike home for lunch today and every time i would hit a bump i would hear a thumping noise. So when i got home I got off the bike and was checking to see if anything was loose. i couldn't find anything. The only thing that made any noise at all was when i would push the fairing into where the Emission Controls used to be mounted(That little black box). So i'm lost as to what is making this noise and could use some suggestions.

It's on a 03 ZX6R

 

Probably low air in your tires. The noise is the rim hitting the ground. That's my first guess.
Next would be loose brake caliper, or loose drive chain.
Then, loose or worn rear suspension component (there's 3 or 4 parts to the rear suspension)

 

My first guess was a loose chain slapping the guard.

 

But it would slap changing gears too

 

yeah it made noise changing gears too. I would've thought low tire pressure but i checked the tires that morning before i left for work.

The chain ended up being loose. I put it up on a stand and tightened it up and it's fine now. I just don't understand how it got that loose that fast. because i checked it that morning also and it was perfect.

 

I had that once and it was a missing bolt from the rear hugger