Thanks for the quick reply's. I think that I need a starting point as I have changed needle jets, pilot jets, main jets, emulsion tubes, drilled the slide, cut the spring, etc. My friends shop gives me access to too many parts, and he is always too busy so I dont like to ask him to look at my bike. Yes I too thought that maybe the CV40 is not big enough but the thing that stops me from putting a bigger carb on is the fact that I only get about 100 miles out of a tank now. I know that with a bigger carb that would probably go down even more. Even with a 46 pilot jet I can close the mixture screw all the way and the bike doesn't die. The mixture screw is not messed up, I have tried 2 different ones with the same results. But with the 46 pilot it backfires through the carb when I take off from a stop sometimes. I have a 48 in now and it doesn't do that anymore. The choke is seated all the way, and in the morning when it is cold, I need the choke on for a few minutes else it will die or not start. So where can I find this Yost kit? It sounds like a good place to start.