Check this: Everybody has heard about retiming the exhaust cam on our WR's. I finally got off my butt and did it. It took me less than 45 min.,including cleaning everthing BEFORE taking it apart. As I expected the bottom was a little softer as well as the mid hit, but a big increase in top end pull. I happened on a thread WRooster posted relating to 250 midrange bog,so I disconnected the same grey wire to the black box. Guess what boys and girls? I have as much or more bottom,major mid and silly YZ top end power. The front wheel lifts in 4th like it used to in 2nd.I haven't even sorted jets yet because i've got a vortip on the way. DO THIS NOW! you will really enjoy your bike afterward. Thanks to everbody for your posts!:cool