I just purchased a 2001 WR426F and am trying to get it in shape. It is missing the silencer & airbox lid (as I read in previous posts adds power). I would like to quiet it down so I done anger the nieghbors. Any suggestions? I won't do it if it will sacrafice the power noticably. In addition, if I crack the throttle (in neutral) really quickly, it dies & backfires. When I am riding it, I don't have any problems becaus I am carring RPM's when I hit the throttle. (It only does it when I crack it very quick).... Is this normal - if not what could be doing this.