dobeck afr+ 2012 flhtk

2012 FLHTK running a Dobeck 4 afr+ 103" 125000miles S&S 551 easy cams V&H power Duals V&H turndown Mufflers K&N 3930 high flow filter. Bike runs great for an hour or so, runs in what i think is the proper range on guage. 14.7-15.1 then starts popping , backfirring, sputtering, running hot and...