I've never had this problem. How many Miles? Have you done a plug check at high RPM. 2-5 minutes at high rpm (70-80 mph in fifth or slower with high revs in a lower gear). Hit your kill switch and pull in the clutch. Coast to a stop. No Engine breaking. Check plugs for color. You may have a cylinder not getting enough fuel. I have read some posts and articles about timing getting off, how that happens is beyond me. Camchains usually don't slip. Another thing to check is TPS (throttle position sensors) on the carbs.
2005 1100 Custom
ORKed 5/16" Lines
PODs K&N RU-600s W/PCV
PCS XXX/2 cams
Jetted & PMS Tweaked 20.0/152.5 3.0 turns
Wimmer Machine Custom Oil Cooler & Stash Tube
Dyna 3000 Step 5/ 6500 redline
6" Fwd Control Extension W/Boards F&R
Memphis Shades Bullet Fairing
Progressive 465 rear
Progressive Springs and GVE front
10,000 Monkeys throwing crap at the glass and this one thinks he's Picasso...