Towards the end of the riding season, my commando was running really great ( which reminds me of the old saying about how things always run best right before they blow up) but I would occasionally hear a grinding sound at idle. Sometimes the bike would sound normal, sometimes not. I have a belt drive so there's less mechanical noise overall than a chain drive primary bike, so I'm pretty sure the noise is not in the primary. I also safety wired everything that might "jingle" like the exhaust rose spiders and anything loose to try to quiet any competing noises.
I don't really have a work space besides the woodshop which is packed to the rafters with stuff and it's winter here with my commando in the vestibule of my house against the stairway wall. If I move the bike into the spare bedroom to work on it (again), then I have to pull up the carpet or it will get ruined (like last time I did a minor rebuild in there) I guess I could also pull it apart right in the vestibule, ruin that carpet this time, and spend most of the winter with a disassembled motorcycle right in front of the main door to the house...
It's just one of those things where I know I have to pull the head and barrels to inspect them, then I have a look at the cam lobes and feel the connecting rods to see if they are solid. My instincts to have a look inside when I hear something that sounds problematic has paid off in the past, and I know better than to ignore my instincts because "funny noises" always have a cause...
I'm also sitting comfortably next to the warmth of a woodstove wondering what I'm going to find, where I should make the mess, and when I should begin...