This is on my 03 KTM 640adv. It has 5500mi on the clock. The usual mods. Valves last adjusted at 1500mi by a good mechanic. Original spark plug. The idle speed was set to aboot 1450, but I recently bumped it up to around 1500 with by adjusting the air idle screw trying to eliminate popping on decel. I have noticed recently that the idle speed seems to hunt around a bit. Only +/-100rpms but it does not seem stable, or as stable as I recall it used to be. It almost sounds like the engine hesitates for a bit, on a regular cycle such that the idle speed stays constant for a second or more and then wags down for a fraction of a second before returning to the idle speed. Does that mean anything to anyone? I was going to put a new plug in first (its time anyways) and if that didn't do it move onto the valves (it's almost time for my first time...). If anyone has any other suggestions I would appreciate it. Maybe this is entirely normal for the LC4's rpms to cyclically oscillate.