I have a 1979 kz1000 ltd that I'm restoring. I've been at it for ayear and a half and getting close to done. I know, it's never "done" but I've got it close. Now I get this knocking banging thumping when I ride it and can't find it. It only happens when it's moving. It always had a little thump that I thought was a tire out of balance but now I wonder if it may be a bering or sprocket or? Any thoughts? the riding season is almost here.