Engine clicking/ticking noise

[FCS]

Hi!

My XTZ660 makes a strange noise coming from the top of the engine and i can't find what is causing it.
The noise can only be heared when I rev up the engine and let off the throttle, or while engine braking. I've already set the valve clearences and checked the timing chain tensioner (when I took the tensioner out, it was in the 10-11th tooth then I pushed it a few teeth out), but the noise did not change.

Here's a video of the engine noise:
https://youtube.com/shorts/GAD7_ZUROS8

On an other forum I've found az NX650 with a similar sound, that bike's problem was loose valve seats.
(https://www.advrider.com/f/threads/engi ... g.1242316/)

Can that be the case with my bike too? Are XTZ660 valves seated like the NX650 valves?
If not, what can cause this sound?

Thanks

[jibber]

Decompression mech?