'07 XR 650L. I recently changed the piston on my XRL from stock to the 10.5:1 JE pistons. Now I hear a slight metalic clank when the engine is idling and I crack the throttle...the sound only comes once right when the rpms start to climb (in neutral)...anyone have any comments on this? My other question is...the fuel/air mixture screw...does turning the screw in make the mixture richer or leaner and where should I be at (i grinded the tab off it). Thanks in advance.