I have a 2006 VRSCD topless, stock pipes were modded, PCIII dyno tuned by the dealer,with 36000 miles. All the maintenance has been done on time. The bike runs great under power but when you run at an even speed it will start sputtering and missing. I thought the valves lash might need to be adjusted so I checked it and it did need adjustment. I did the adjustment and thought that would stop the rough running, but it didn't help. Any advice anyone?