Choosing oil for a bike depends mainly on which bike - BMW and Moto Guzzi use ordinary automotive oil, and the rest, which have the clutch in the same oil as the motor, should use motorcycle oil, but can normally use auto oil ok.
There has been a lot of discussion re what mc oil really is, and the main conclusion is that they are designed with the presence of the clutch in mind, and the higher rpms that bikes run.
SOME oils, particularly synthetic, have been reputed to cause clutch slip, but this is mostly anecdotal, and has never been reported to be serious.
You will generally find that any decent quality oil will work fine. The better quality/brand the oil, the better of course. I would not recommend carrying oil, unless you use a lot, and you should then fix the problem asap.
Generally if there is some semblance of a road and petrol/gasoline station, there will be a useable oil. I may not choose to change oil with some of the weird stuff I find off the beaten path, but topping up with it should be fine. Plan oil changes in larger cities.
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