Just a few decades ago, there was little to no distinction between automotive motor oil and motorcycle oil. These days, the two lubes are quite unique. What are the differences, and more importantly, what happens if you run car oil in your bike?
Motorcycle oils branched off from automotive oils in the 1980s as car oil evolved in a way that caused problems for motorcycles. Specifically, friction modifiers designed to improve fuel economy could cause a bike’s clutch to slip under acceleration.
For the most part, the “it’ll make your clutch slip” explanation is all you’ll hear when it comes to running car oil in a motorcycle. That’s not a guaranteed outcome, and frankly it’s just the tip of the iceberg. There are other differences that make auto oil unsuitable for motorcycles, and it has to do with the fact that bikes usually rev higher and run hotter than cars, and unlike autos where the oil only lubricates the engine, in many motorcycles the same oil serves the engine, clutch, and transmission.
Automotive oil vs. motorcycle oil: What riders need to know
American Buddhist Net 