It is my understanding that motor oils have been formulated to 'meet or exceed' previous specification standards. I have run older bikes for some decades now and have never realized a problem using quality oils of suitable viscosity.
Dave
'76 CB550F
'86 GTR1000
I use Shell Rotella 15W40 with good results. Automotive oils with the energy-saving logo should be avoided because friction reducers can cause clutch slippage.