If you don't mind me asking, how do you know that your chain is adjusted right? If I'm in a hurry I'll use the "3 fingers between the chain & swing-arm" method. Otherwise it's 2.2" on my KX250FGuys I think my chain is adjusted right but when cruising 30-40mph just down a dirt road my chain sits there and clatters. Do I need to loosen it or tighten it or is this just normal? Its annoying that is for sure.
Try it and see what happens, you can always put it back.I just set it according to the manual. Its just at a steady pace. If I'm pouring the coal to it it doesn't do it and if I back off the thottle it stops. I'm worried about getting it too tight so maybe I should go to the tighter end of the adjustment they allow? If I remember is like 1.9" to 2.5" of slack. (Thats just off the top of my head.)
when cruising at low to mid rpms the chain will clatter on the hollow swingarm making quite a racket. James is right to be sure the adjustment is right too.
Try it and see what happens, you can always put it back.