Hi, I (my son) have a '99 XR100, it has an uncorked stock muffler with homemade endcap. The modified muffler seemed to help it breathe a little better, but I have recently cut the mesh screen out of the airfilter cage, and am looking for advice on where to start with the jetting, as it is running a bit lean now. Stock main is a #96. I have fitted a Dynojet #98 I had lying around, but still feel I could go larger. Has anyone any suggestions on how large? I am at sea level, thanks, Chris.