I just installed mine this weekend. When you buy them they should send them to you all ready set up for your bike depending on what you have done. The jets are #erd as 58, 60, 62, etc. I have 60 in mine and I am running t-5's, k&n no air box, noss head, 20cc domes, and I am at sea level. Bike runs great with those jets. Hope that helped!