I cannot silence the tappets on my Himmie, even though they are adjusted to spec. Bike runs and pulls really well though.
Maybe it's not tappet noise....
I helped rebuild the engine of the passing tractor at the end, it sounds more healthy (and the tappets are way more easy to access and set!!)
https://www.bitchute.com/video/6JhUaaSMgxBm/
I've seen your post on a couple of sites, sorry but I am going to pepper you with questions, hope you don't mind.
So, how many miles on the Himmy? Is it a 2018-2019 FI model? It looks pretty much stock, any internal engine components been changed out besides the cam adjuster? Does it have the same sound when cold and after a ride or does the quality of the sound change and how so?
About the video, it's a bit hard to get a really good feeling from it, it seems that some audio is shifted upwards or perhaps there is a high'ish drone from the microphone or from the encoding process. I hear both normal and not normal sound at points, the phantom ringing and high's pitch drone when the tractor goes by is what confirmed the audio being off kilter.
OK, here comes the shotgun approach as there isn't enough info yet to really isolate the fault or tell if it is a fault.
Overall, do you find the tappets themselves loud or are they fine and there is a rattly resonance as described above when decelerating the engine, or some variation of those symptoms?
About noise and rattly bits, the oil pump chain and sprocket is very loose by design, this is non-critical though a small amount of sound could originate from it. You can remove some of the play with a small shim, but its fine as it is. If its pumping oil along with adequate pressure, it is not broken.
Valve guide wear which I doubt as you should get a bit a telltale of grayish smoke.
If you have read this far, thanks.
If you could re-record the sound, but perhaps on a smallish pad of concrete but definitely outside of the enclosed space and away from walls it might be helpful to the ears to discern more info. Also, my eye can't help but look at what might be a hole in the spark plug boot. lol Good luck, I hope we hear back from 'ya.