Motorcycle oil in a car engine

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Jul 29, 2003
Kyiv, Ukraine
According to oil and bike manufacturers their motocycle oils have superior wear protection, engine cleanliness, high-temperature stability, lower volatility/lower oil consumption and often better anti-corrosion performance. For a.m. reasons it is not recommend to use passenger car oils in bikes. OK, most likely it's true. Then why would not we use a good motorcycle oil for 4-stroke engines in a car engines ? Think we may disregard an impact on catalytic converters for the following reasons: 1). lower volatility, if it's so, should offset a higher phosphorous level; 2). higher phosphorous does not yet mean this will damage the converter faster because the process of its giving off depends more on additive chemistry; 3). gas is not perfect everywhere too and it may content so many impurities that they can kill converter earlier then phosphorous. Where the truth ?
The M/C oil works great in a car. The reason the car oil don't work so well in a bike is moly that a lot of them have. Put a heavy enough clutch spring and that doesn't even matter. They are all engines internal combustion, gasoline. Pour in your favorite brand in the correct weight and don't worry bout it. The heavy duty 15W40 and 5W40 oils work well in bikes.
Main reason I can think of is friction modifiers. Motorcycle oil is shared. It goes from the engine to the tranmission and clutch and back. That's why you change motorcycle oil more often. Motorcycle oil doesn't have friction modifiers in it because of the clutch. Wouldn't want that thing slipping.
Well, the situation when a car engine oil is used in bikes is more or less clear, but how about to use a bike oil in car engines ? Naturally it's considered 4-stroke motorcycle oil only.
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