Cam chain possible but unlikely with that little miles on the bike. It is possible that the hydraulic adjuster on the left cylinder is passing but against n would be the first I have heard of that wearing that quickly.
Penny in a can sounds like a cam but the fact that it comes and goes and flips side to side does not fit the diagnosis. Could also just be an adjuster that backed off on the rockers. Did they actually pull the covers off or just guess.
See if you can confirm that the sound is actually coming from the Valves. Screwdriver to the valve cover and then your ear will work. Do the same on the gear box, the bell housing and also the front of the engine where the alternator belt is. You will pin point the sound other than guessing.
Recheck the clearance and see where they are. See if you can upload the sounds to you tube and then post a link. Other way is to change the file extension name to .pdf and then upload it to a reply. Just tell us what the extension is supposed to be and then we can download it and change it. That should work.
Penny in a can sounds like a cam but the fact that it comes and goes and flips side to side does not fit the diagnosis. Could also just be an adjuster that backed off on the rockers. Did they actually pull the covers off or just guess.
See if you can confirm that the sound is actually coming from the Valves. Screwdriver to the valve cover and then your ear will work. Do the same on the gear box, the bell housing and also the front of the engine where the alternator belt is. You will pin point the sound other than guessing.
Recheck the clearance and see where they are. See if you can upload the sounds to you tube and then post a link. Other way is to change the file extension name to .pdf and then upload it to a reply. Just tell us what the extension is supposed to be and then we can download it and change it. That should work.