yikes!! if your chain is that loose you might want to check the pinch bolts are tight. from what i get out of what your saying if indded that chain is so loose it had enough sag to drag along the swing arm or worse yet to be sliping on the sproket.....holy tore up chain and sproketscyprusrappy said:I hear noise too. It could be from the roller but it could also be from a loose chain. I thought it was something in the front of the bike but reading this makes me certain its from the chain. I was almost sure it was from the front wheels but it did it mostly when you let go of the throttle so which means the chain losens up and rubs along the skid and roller.
Ill check it better tomorrow.