I put a Dynojet kit in my Foreman about a month ago. Like you, I followed the directions in the package, and put in the 126 jet. The smaller needle is why they start with the smaller jet. Mine also ran lean set up this way. I went back and put the 130 jet in, I left the new needle set up like the instructions recommended. I used the 130 jet in the kit , not the 130 that came out of my carb. Not that there is any difference in them.
After changing to the 130 jet, it ran like it should. I put the kit in after changing to a UNI filter and an HMF pipe.
After changing to the 130 jet, it ran like it should. I put the kit in after changing to a UNI filter and an HMF pipe.