New to me 1981 CB750 Custom (DOHC), and I can't get the timing chain(s) to stop slapping, they just fall out of adjustment or slap at deceleration, acceleration, etc. so Imma thinking the cam chain tensioners are no longer doing their job (based on my web searches). I'm more of a parts changer...
It's a 1970 sohc .... I cleaned the tensioner during the rebuild, not sure of the adjustment process. Also, is the hole in the end of the piston housing supposed to be plugged?