SauRoNZA
Honorary Master
Engine manufacturers design their engines around the type of oil that they intend to use in it. Not the other way round. The oil journals and clearances are specific to the type of oil that they intend on using. So you're welcome to put diesel oil in your bike, and it will probably work fine, but its not really designed for it.
No I’m literally telling you that some bikes use the EXACT same Diesel oil rebranded as motorcycle oil.
Motorcycle oil has anti foaming agents that car oil does not need, so when you're revving at 12K RPM the oil doesn't churn up. Car oil doesn't need this because most car engines barely rev past 6000. Not to mention car oil doesn't need to worry about shear resistance caused by meshing gears, because its no where near the gearbox. These additives in bike oil will make your bike engine and gearbox last longer than using car oil. So by all means, make use of car oil if you have to, but neither the manufacturer nor any reputable mechanic would recommend it.
I never said use car oil...and I’m not advocating it.
But as per your very example not all bikes even rev to 12k either and it’s those very same bikes that use the exact diesel oil I’m referring to above.
My point was that all bikes aren’t the same and in many cases oils are simply branded differently on the shelf while being the same thing under the hood for a given purpose.

