I just bought a 05 1100 custom it has the hard krome exhaust on it. I noticed a backfire from the rear cylinder from the pipe and the carb pops too. I jetted the carb with dyno jets. I also compressioned tested it it was about 105 PSI while the front was 120 PSI. I turned the carb around and the problem followed to the front cylinder then. I also checked the plugs and wires. the plugs are brown which is good. The AIS is totally removed and the applicable items are plugged. I am running a 112 jet on the front and a 110 on the rear. 2 1/2 turns on the PMS screw. I also frabicated a restrictor in which I installed just to see if it would work on the rear exhaust still no work then tried one on the intake to see no luck also. I have also tinkered with the PMS screw to see if tht helps but it doesn't. I can't think of anything else to do. It pops on decel, idle, and when reving it up. Any help will be appricated, I am spent.