New to the site and have to say that it is an excellent source of info. I have 2000 WR 400 and am currently doing all the free mods and some the not so free mods. I read in a couple of postings on this site that say to use the YZ jetting. I am curious if this is year specific. Meaning since mine is a 2000 do I need to use 2000 YZ or any of the years. Thanks and look forward to reading more.