2009 GZ 250 makes a scraping noise when it accelerates
 

It just started a couple days ago, but when I accelerate there is some sort of scraping noise, like something on the back tire has something stuck to it or something shifted...however, when I pull in the clutch the noise disappears.

I did a visual inspection and found this small rubber hose hanging, problem is I have no idea where it came from.
Please help!

If you trace that hose back to it's source, you will find that it is a drain hose that starts at the bottom of your fuel bowl on your carburetor. It has nothing to do with your noise.

Not sure what is causing it, but check to make sure your rear axle is aligned properly so that the front and rear sprockets are parallel and also check your chain tension. You shouldn't have more than about a 1/2 play in it at mid length. Hard to diagnose.

I am sure others will come on here and give you some other things to check.

..and when you tension the chain, rotate the wheel to make sure it isn't too tight - those sprockets aren't always perfect circles.