I see where its slid under the joists in spots !
I would disconnect from the light and put it under but technically the joists should be drilled and the wire passed through properly.
Used to know a guy who had one !
he could make that bike sing you always new when he was coming and going he was merciless to that bike and hammered it through every gear any chance he got.
Actually quite surprised he didn't kill himself on it
Yes !
I changed two not long ago like you one was set to cold and the other perfect around 120f.
for him I think this issue just cropped up on existing valve .
Good luck !
hopefully its only carbon but that looks like metal flakes to me and I'm 99% sure that its the camshaft alignment pin being ground away .
If you get it figured out and running well I suggest 3k oil changes on it.