Possible Engine Sound

[His Dudeness]

You could check the clearances yourself. It's a bit fiddley but not that hard. The clearances on a fazer are more likely to tighten as the valve wears into the head so they get quieter which is worse because the smaller clearance means the valves are held open longer so they have less time to cool against the head which is why they burn out if you leave it too long between adjusting them. Not saying that's likely on your bike it's just what happens eventually. The older style tappets tend to loosen so they get louder and you hear the distinctive tappet sound.