Hey, I read on Eric Gorr's site that on a 98 CR125R you can put a CR250 Carb on to get more top end. It had the Jetting and Needle recommendations, but my bike is not stock I have a FMF Gold Series SST Pipe on it and the stock carb was re-jetted for the Pipe. What Jetts and Needle sizes should I use and what should the clip position be to make the 250 carb work on my bike?
I'd start with Eric's recomendations as they will be pretty close. A pipe and silencer doesn't make much difference in jetting. Eric's specs will get you in the ballpark then as always you will need to fine tune from there.