K4.... CB750? The answers are dependent on this vital information.
There are tons of information about this and exactly how to do it. Just search.
Replace the prim chains at the same time which can be done whith cases apart crank shaft liftened. Replace the cam chain at the same time with it's tensioiner.
Repairing an old engine will start a domino effect....bearings, clutch plates w springs, all chains with tensioners, valve job/new valves with cut seats, complete gasket set with ALL o-rings and seals on all shafts...
My CB750 runs very silent with new chains, all are heavy duty versions. I think the HD prim chains run more silent than OEM. Cost 3 times more though...