Ok Guys I finally bought the JD Kit for my bike today. I have a 2004 wr450, I just bought the JD Kit and the FMF power core 4 with the quite core insert. I would consider myself a decent wrench But I am not ashamed to admit that I know absolutely nothing about re-jetting a carb. Can I get some pointers from a few that have done this? I plan to be running from sea level to about 4000ft. Oh yeah I will also be popping open the Air box as well. Thanks in advance for all your help.