Could you possibly be able to record this ? and upload it to Google Drive , then get a public share link , post the link here to view it. But do check the clutch basket , rattling is something spinning, so I hope it is just a thrust bearing for the clutch or 1 clutch plate that has worn down too far and it has cracked (Happens actually) then its just clutch overhaul job. Tensioners Cam = I am not sure what to say just yet until you get it running fully or check the flywheel area to see if the sprag clutch is making noise there ? or a rattling worn out starter motor ? Just have to find the source of the noise as far as you can.
been trying to figure it out and then i had things to do but now i have done so
https://drive.google.com/file/d/1JSbKA8OWm4KNXcqw2iLHa1N-T33WRXqE/view?usp=drivesdk