Just to reiterate, my ZX6R, Versys, my buddys Z, all had "ticking". That is ussally the CCT. Resetting it as required due to the valve job should do the trick. But keep in mind it will probably come back, and thats ok if its CCT ticking. Now if its a tapping noise or dull dapping then that's different. My ticking kinda sounds like a sporter engine. And sometimes it's not there, other times it is, and sometimes it's louder, but then eventually fades away as the CCT adjusts.
Before buying my DS70 exhaust, I listened to a ton of videos of different exhausts on youtube. If you listen to enough, you will hear the ticking I'm refferring to on a lot of ER6N, Versys, and 650R.