Today when I was changing the battery on my bike I was also checking the chain. I but the bike on the stand and started the motor and put 1:st gear in. Then I was looking from behind on the wheel, this was going strait and looked good. But when I was looking on the chain and specifically on the sprocket it looked like it was going strait but with a "knock". Could it be the sprocket that has been damaged? I have had the wheel removed to change the tire and then I put it back. But the thing that worries me is that the fact the wheel is going strait. Could this cause any damage? I cant feel anything when I am driving the bike...