A month ago my 00 WR400 ran great. I had richened the jetting a little from stock due to colder weather. Stock jetting was: 165 main 42 pilot 3rd clip on needle fuel screw 1 1/8 out 1st change was: 168 main 42 pilot 3rd clip on needle fuel screw 1 3/4 out Ran really good! Then the weather change. Since it has gotten a little colder I have tried: 170 main 42 and 45 pilot 3rd and 4th clip needle fuel screw 1 to 3 turns out. 168 main 42 and 45 pilot 3rd and 4th clip on needle Fuel screw 1 to 3 turns ou 165 pilot 45 pilot and 42 pilot 3rd and 4th clip on needle fuel screw 1 to 3 turns out But it still is really slugish on take off and throughout the whole spectrum. It starts pretty easy after warm up it idles ok then after you ride for about 10 or 15 minutes it goes to crap. Won't idle and when you let of the gas while riding it goes dead it is hard to start back up. When going through the gears it's coughing and sputtering like it is going to kill over any second. I tried to give every setting about 15 or 20 minutes of riding, I was by myself so I could really pay attention to how it was running. But all settings had about the same results. CRAP! After every setting I have checked the plug: sooty around the base of electrode and a little up it but on the horizontal part it is dark grey but no soot, just bare. I live in Reno the elevation is about 4000-5000 feet. Have a White Bros. silencer with stock head pipe, 12 discs. Air box lid removed, stock air filter(clean). Emptied tank of gas thinking maybe bad gas, no such luck. Have maybe I lost my mind and headed in the wrong direction? Should I try a different needle? Any help will be greatly appreciate. P.S. A guy I met Sat. while broke down says he richened up the main to a 168 other than that the jetting is stock and his runs great. Why is it two identical bikes bought from the same dealership ridden in the same area are so different?