Valves going out of adjustment make less noise because the gap turns into nothing. Should have a very slight ticking sound. I've heard quite ATC engines, and the valves were too tight, no slack at all, which is risking a burnt valve. When the valve contacts the seat, it disperses heat. If the valve doesn't fully contact the seat (too tight) it can overheat and burn (melt a groove in the valve seating area).
Metal shouldn't be coming from the clutch. If it isn't' slipping or dragging, it's fine.
What you may have heard and seen was one of those, it didn't hurt it, but didn't help it moments. Otherwise known as, keep riding it and don't worry, nothing to do about it.
If it's due for an oil change, why were 'running it hard' and pulling a trailer?
Like a goomba would say...fuggedaboutit.
The story of three wheels and a man...