I am aware of a whining noise whenever I pull away and I understand that this is normal for kawasaki's although, recently after coming from a mud run I've noticed a knocking noise coming from my quad at about 10km/h-30km/h. It's not that loud but it's starting to raise an eye brow or two. Sounds like grinding gears? or something with the drive shaft? I don't really know, if anyone has any suggestions or ideas on what it could be it would be appreciated.