I did not see a 125 listed in Matt R's sticky of the jetting database.
With the '01 XC125 we had at the shop:
AS1 Keihin
N1EF needle with the clip in the third position
40 pilot
180 main jet
This was before I learned a lot of the info about the jetting that I now know, but it worked pretty well.
The bike was super sensitive about the jet needle and which groove the clip was in. Just a shade too lean and it had no bottom end power. One groove on the needle made all the difference when riding the bike in the mountains. It went from a nightmare ride to a rocketship with good low/mid-range torque.