I have a very similar set-up on my ZX50. I ended up having to run a 25 pilot and a 115 main jet. Can't remember off hand which position my needle is in, I think in the top clip. Mine does sputter a little when it's cold for the first 1/4 throttle, It's all good when it's warm though. It seems really difficult to get the Arreche to have a nice smooth transition all the way through. I think ultimately I need a different needle, just haven't seen any available anywhere.