I have a 03 wr 450 with a bout 200 miles on it. Last summer it started missing, popping, stuttering past 1/3 throttle then cleared.I read about the woodruff key problem and had the dealer make the repair. The first owner had the following mods made prior to the bike leaving the dealer. Big Gun exhaust with header and air box mods. This year, I cut the grey wire, placed additional mods to the air box cover and installed a JD stage1 jet kit as directed. Well guess what? The problem is back. So, I completely dissassembled the carb and cleaned all the passages and even tried jetting changes. The result was a leaner or richer running machine with the same problem. I figure that since the problem begins past 1/3 throttle and does not go away, it has nothing to do with the carb. In my last effort tonight, I replaced the plug thinking it may be just that simple. We will see what happens tomorrow. If any one has some ideas, thow them my way... Thanks!