Have an 08 superglide purchased new and like most of us on here gets the best of care. had a stage 1 done at 1000(SE air cleaner,SE tuner,V&H slip ons) miles and everything was good till about 6000 miles. Pinging when cracking the throttle in 4th or 5th(tink,tink sound).Changed plugs SE plugs I used Harley fuel additive drained fuel tank fresh fuel, no change. my next step was to change out plugs went one step colder(ngk plugs) and now am trying starbrite fuel additive and have done a lot of reading on using the pro tuner software,i have made some changes in acouple of tests(minor to AF,VE,and Retard timing a degree) last flash seems to have quieted it down a lot and unlike the other flash has not lost any HP. I have not changed anything when this occurred same fuel from same station (93 octane) no other mods were performed. One thing I did today took out plugs and I used inspection camera and noticed carbon on top of both pistons, some flaking on top maybe additive working? I have heard this motor is sensitive to increase in compression? could this carbon buildup cause the pinging problem?