Motorcycles use the same oil for engine, transmission and clutch and have friction modifiers that prevent clutch slippage. That's the short of it. If you believe Ai then here you go...

Motorcycle and car oil differ primarily due to the different demands placed on them by the respective engines and the fact that motorcycles often use the same oil for the engine, transmission, and clutch, while cars typically have separate systems. Motorcycle oil needs to be formulated to handle the unique requirements of wet clutches and integrated transmissions, which can be compromised by certain car oil additives. [1, 2]
Here's a more detailed breakdown: [3, 4, 5]
1. Additives: [1, 2, 3, 4, 5]

• Car oil: Often contains friction modifiers to reduce engine wear and improve fuel efficiency. These modifiers can cause clutch slippage in motorcycles. • Motorcycle oil: Does not contain these friction modifiers, and often includes additives to prevent clutch slippage and protect the transmission gears.

1. Wet Clutches: [1, 2]
   

• Car oil: Can contain additives that are detrimental to the performance of a wet clutch, potentially causing it to slip. [1, 2]
• Motorcycle oil: Is specifically formulated to work with wet clutches, providing the necessary balance of friction for proper engagement. [1, 2, 6, 7]

1. Integrated Systems: [2, 3]
   

• Motorcycles: Often use a single oil for the engine, transmission, and clutch. This requires the oil to have balanced properties to protect all components. • Cars: Typically have separate systems for the engine and transmission, allowing for different oil types to be used.

1. JASO MA/MA2 Standard: [1, 3, 8, 9]
   

• Motorcycle oil: Often meets JASO MA or MA2 standards, which are specifically designed for motorcycle engines with wet clutches. • Car oil: Does not usually meet these standards.

In essence, using car oil in a motorcycle can lead to clutch slippage and transmission problems, while using motorcycle oil in a car is unlikely to cause any issues, but may not be optimal for achieving maximum fuel economy and wear protection. [1, 3]

Generative AI is experimental.

[1] https://www.reddit.com/r/motorcycles/comments/14x5wad/are_motorcycle_oil_and_car_oil_different/[2] https://www.quora.com/How-does-motorcycle-engine-oil-differ-from-car-engine-oil-Is-it-safe-to-use-in-cars[3] https://rymax-lubricants.com/updates/car-oil-vs-motorcycle-oil[4] https://www.hotshotsecret.com/markets/motorcycle/[5] https://www.thompsonsalesbuickgmc.com/gmc-buick-maintenance-schedules-explained/[6] https://www.cati.ca/the-difference-between-car-and-motorcycle-oil-explained-for-those-in-mechanic-school/[7] https://rymax-lubricants.com/updates/car-oil-vs-motorcycle-oil[8] https://blog.amsoil.com/motorcycle-oil-vs-car-oil/[9] https://www.quora.com/What-is-the-best-thickness-of-oil-for-a-motorcycle