Hi, i have a wr450 03 model, all free mods + aftermarket wileyco exhaust. i had the standard needle and main jet was 160 and 48 pilot and it didnt run too bad. I bought a JD jetting kit and installed the 168 main jet and red needle on clip 5. It ran alot smoother at midrange - it used to have a bit of a rough misfire or something. BUT when the revs get to top end it would burble and struggle like it was way too rich. So i changed the main jet to 165 and it got better but it still struggled a bit. Now im back to 160 and its almost back to normal i think. the tempreture is only about 15 degrees celcius and im about 250 metres above sea level. The bike felt like it had more power with the larger jets and everyone else runs a 168 with no problems. what could be causing the bike to be soo rich up at top revs. any suggestions to what i should do? I also installed the rubber o-ring on the fuel pump acctuator and now it has more punch from that mod. i dont want to stuff around forever with my jetting so i thought i ask for some opinions. by the way my air filter is clean and not overoiled and my airbox is opened up. Thanks for the help in advance.