I just bought this '03 WR450 a month ago, so I'm new to the tuning steps. Once my bike is fully warmed up, when the throttle is revved, the rpms remain high for a couple seconds before dropping back to idle. It does this in gear while moving as well as in neutral on the stand. It seems to hang on longer than normal. I've also noticed that the rpms sometimes fluctuate (increase) at idle for seemingly no reason. Any ideas?