Why you shouldn’t use car engine oils in motorcycles!

If engine is the heart of a motorcycle, engine oil is the life blood, without which the motorcycle would literally cease to function and suffer a cardiac arrest.

Yet, when it is time for an oil change, people knowing or unknowingly purchase the wrong type of engine oil or leave the decision making process to the wrench monkey, who only gets his banana, when your motorcycle develops a problem!

One of the most common mistakes we see people commit is buying engine oils which were meant for cars eg. Castrol GTX, which is fine if you own a Royal Enfield or similar type of motorcycle, where the gearbox and clutch plates are separate from the engine. However for nearly all the motorcycles being currently sold in India, including the RE motorcycles with UCE engines, it is a sure shot way of inducing clutch slippage, which in turn leads to low clutch life, less performance and lesser mileage!


In a car engine, much like that of earlier Royal Enfield motorcycles, gear box and clutch plates are housed separately from the engine and are lubricated by gear oil. Which is why car engine oils have friction modifiers which stick to engine components to reduce friction and help engine operate smoothly. However these friction modifiers are bad news for the clutch plates, as clutch plates need friction to operate!

Think of it like this, while wax polish is great for shining motorcycles, it isn’t a good idea to use it to shine your bike’s disc brake, because then brake pads wouldn’t get any friction and won’t be able to stop the motorcycle in time or worse still, not at all!

How can you tell, whether or not an engine oil is fit to be used in bikes?

Well it is quite simple actually, thanks to the Japanese Automotive Standards Organization, who came up with JASO MA standard for motorcycles. JASO MA and JASO MA2 standard ensure that engine oil is free of friction modifiers and is fit to be used in motorcycle engines.


If there is no mention of JASO MA specification on the bottle of engine oil then do not buy it, irrespective how many praises you might hear from its seller.

Apart from this, make sure the engine oil meets the minimum viscosity index eg. 20w40 and API standard recommended by your motorcycle manufacturer (this is usually mentioned in motorcycle manual) and your motorcycle’s performance would remain top notch.


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  2. Castrol GTX 20w50 works excellent in my RD350 and Shaolin

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  5. somebody pls tale me that how much engine oil is required for stunner 125cc bike (800ml or 1 liter)

  6. Who said one cannot use a car engine oil for a 4 stroke bike. I have been using only Castrol GTX or Castrol CRB plus for my HeroHonda Splendor 1994 model which I bought brand new and which has clocked so far about 74000kms. No clutch slippage or engine damage so far. It still gives about 65kms mileage on an average and no unwanted noises from the engine or gearbox.

  7. If it is working for you then great, however it is best to use motorcycle engine oils for above specified reasons. If this wasn’t the case, there would be no need for JASO MA T903 certification and engine oils being specifically made for motorcycles. Not to mention, one of the oils you are actually claiming of using is meant for diesel engines!

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  9. neelesh jain says:

    thanks a lot…articles like these help newbies n budding bikers a lot…thanks again for sharing… 😉

  10. neelesh jain says:

    thanks a lot…articles like these help newbies n budding bikers a lot…thanks again for sharing… 😉

  11. Yogesh, Castrol CRB plus can be used in petrol engines too. It has the added advantage of having a blend of very good detergents in it.

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  13. thanks but, still i am in trouble to parches oil foe my stunner
    either 20w40 or 20w50

  14. Castrol CRB PLUS is very good for 100cc bikes. It gets more smoothness and work very well in long runs and during tough weather.

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