Ron,
Not sure its all related to just AFR in this case. It maybe related to getting the heat out of the cylinder or cooling of the cylinder or a combination of both. As you were there you know both cylinders were set equally and independently. I may try and tune the bike again for 13.4 to 1 and see if it helps at all. Seminole HD shop said that they arent seeing the heat problem with the 2 into 1's like they are on the true duals. Not sure how suspect that is, but with Brian owning a 110 Roadking with the Rinehart 2 into 1 we should be able to tell over the next few months as he puts miles on the bike. Jim B also likes the Rinehart 2 into 1 for making power on the 110 seems to be putting up the best numbers on his dyno.
It's always something to fool with.