Journeyman
"And this one is just right" ~ Goldilocks
By the rev question we (@Nashvegas, initially) meant when you hear it at idle what happens if you give it a little throttle? Speed up? Go Away?no its definitely not heat shield, its something coming from top of engine near head or something,
I dont rev hard, i ride mid range 4K RPM and once its get hot then I start hearing it,
it was not happening when bike was new like 6K miles or 10K miles, it developed gradually over time for sure.
Lots of other good ideas since then, like the stethoscope or vacuum hose to pinpoint the location of the sound and checking for exhaust leak. If that's bad enough you'll notice more popping on decel.