Sorry for the essay... So I am a newbe to dirtbiking and like when I got started with driving I love to learn about the mechanics of the bike as I start to ride. One of the things I am pretty confused about is the carburator and the different jets. I hear things like pilot jet, main jet, etc. But I really dont know what any of that means. I did a quick search and didn't see anything. I am sure there is a sticky on the subject somewhere, but if not, can someone give me a quick run down on what are the parts that are adjusted to tune a bike. Also any pictures would be helpful. I am currently in the market for a XR 200/250, TTR 225, KLX 300 ranging anywhere from late 80's to present. Basically a 4stroke from the 200-300cc range. Also what are common terms you guys refer to when describing how a bike is running so it is easier to communicate with others? Finally, how can you tell what jets are in a specific setup? For example, my roommates TTR 125 is all stock but it has a hell of a time starting when cold. Once warmed up it has a solid idle and has good power through the whole RPM range. I dont know what it is about starting it, but after a day, it will take 20+ kicks to start. Where would be an apporopriate place to start?