Use anything with the Honda specified weight except new oils with friction modifiers. The clutch will not like low friction oils. Some people use JASO approved oil. I use oil designed for Diesel engines. Some people add zinc additives. There are a lot of opinions and very little science regarding these engines. The main thing is to keep it clean.
I just brought two quarts of the same Quaker state SAE 30. It has been working out ok. I tried Castrol 30 a few years back and it seemed thinner, and my clutch was slipping. I read that these old bikes should use non detergent oil.
I believe the idea behind that is that the detergents are supposed to be so good that they wash the gunk out of the centrifugal oil filter. I would speculate that filtration would be more dependent on particle mass than solubility in the detergent but can't say I know enough to provide you any guidance.
I chose rotella t4 10w40 for my cb160, added some zinc additive just in case
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