Everything you need to know about bike engine oil explained

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everything you need to know about motorcycle engine oil explained
8 December 2023

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Long story short: Motorcycle engine oil change is mandatory every six months, irrespective of kilometers.

Engine oil is something like blood for humans in comparison. It is so vital that without it, both cannot live. Engine oil performs various critical functions that are mandatory for a long life. In India, as bike owners, we have limited knowledge about the type of engine oils and engine oil grades. Oil change frequency, etc. We rely entirely upon motorcycle technicians to get the job done. Yes. But our take regarding the same is that we should not unquestioningly believe the words of a single person and at least have the basic knowledge. In this article, we are here to share some ideas and tips related to bike engine oil in the most straightforward manner.

How motorcycle engine oil works

Motorcycle engine oil minimizes friction and wear between the engine components. Engine oil forms a film on metal surfaces to reduce friction. Reduced friction prevents heating and abrasion on the friction surface, such as engine bearings.

What are the functions of bike engine oil?

The functions of engine oil are to minimize friction, reduce wear, clean the engine, cool engine parts, form a seal, dampen shock, and prevent corrosion.

Types of motorcycle engine oil

There are mainly three types of bike engine oil, and they are

  1. Mineral Oils (MO)
  2. Semi-Synthetic Oils (SS)
  3. Fully Synthetic Oil (FS)

Now, let’s explore each type of motorcycle engine oil in depth.

Mineral Oil (MO)

Mineral oils are a product or by-product of petroleum processing. It is the cheapest and is for small-displacement engines. Small displacement engines are never meant for high revving and do not exert too much stress on the machine. Brand-new engines or motorcycles use mineral oil as it provides good protection. However, the downside is that mineral engine oil requires frequent changes and does not last long.

Semi-Synthetic Oil (SS)

As the name recommends, Semi-Synthetic Oil provides the best of both worlds: a high level of protection from mineral oils and high-performance aspects from synthetic oils. This bike engine oil is recommended for 150-300cc motorcycles and will cost more than mineral oil. If the engine capacity is below 150cc, then opt for mineral oil.

Fully Synthetic Oil

Fully synthetic engine oil is the most expensive oil of all types. While mineral oil is derived from natural products, synthetic engine oil is constructed from pure polymers. Synthetic oil is recommended for high-performance motorcycles like off-roaders, superbikes, and racing machines. The main advantage of synthetic oil over mineral oil is that they do not degrade fast and last longer. Another USP is the high lubricating performance it provides.

What is an engine oil grade?

Engine oil grade is a set of specifications or codes mentioned with the engine oil. It mainly says which engine oil is according to the external environmental conditions. More technically, engine oil grade refers to the viscosity or the resistance to flow. The lower the number, the better it will flow.

How to read engine oil grade?

The name SAE number also refers to the engine oil grade code. SAE refers to the Society of Automotive Engineers. The letter W refers to ‘Winter’ in the code. The first number relates to how oil flows when cold, such as at an engine start-up. The second number is defined by how oil flows at higher temperatures than standard engine operating temperatures.

Thin, low-viscosity oils flow easier to protect engine parts at cold temperatures. Thick, high-viscosity oils are typically better at maintaining film strength to protect engines at high temperatures. For example, a 5W-20 will flow more effortlessly than a 10W-20 at start-up temperatures, and a 10W-40 will flow more effortlessly than a 10W-50 at regular engine operating temperatures.

The chart below recommends engine oil with the outside temperatures.

motorcycle engine oil grading system

When to change motorcycle engine oil?

Engine oil must be changed every 2500-3000kms or every six months, depending upon the type of engine oil. Synthetic and semi-synthetic oils last longer, so ask a bike technician or shop owner for the same. In the case of mineral oil, oil replacement is recommended every 2000-3000kms. Anyway, an oil change is mandatory after every six months, irrespective of any other aspects.

What happens when the engine oil change is late?

A delay in engine oil change results in performance loss and a drop in fuel efficiency. Overall, it affects the life of the engine and the vehicle.

How to check for bike oil replacement?

Check for the engine oil color by loosening the engine oil bolt and dropping oil in an oil pan. This method varies among models, and there are other ways for some models. If the color is dark, it is time for an oil replacement. Brand-new engine oil is always clear and almost transparent.

Is it mandatory to change the oil filter while changing the oil?

Yes, when you change the engine oil, you should also consider changing its oil filter. An oil filter’s role is to protect the engine from potential damage by removing contaminants that can accumulate in the motor oil. Just like the engine oil, the oil filter of your bike gets clogged or damaged after a particular time. Change the engine oil filter once a year or after every two general services. Check for the same in the owner’s manual also.

What is bike engine flush?

An engine flush is an aftermarket chemical additive that cleans accumulated engine sludge and deposits.

How to flush the motorcycle engine or engine oil?

Add the engine oil flush to the crankcase before the regular oil change. Oil flush cleans the interior parts from sludge and grease deposits, leaving them fresh for new lubrication.

For that, check the same in the owner’s manual. Oil quantity should not be high or low; service manual rules should be strictly followed. As the owner’s manual mentioned, the oil quantity should be higher when changing the oil filter. The last point is critical to note.

Should the bike engine be warm while changing the oil?

Yes. The engine oil is thicker and colder during the early morning hours. So, for oil to get loose, drive the motorcycle or warm the engine for some time.

Does motorcycle engine oil burn?

Yes. If there is an issue within the engine components like piston rings, oil deposits can accumulate on the engine spark plugs or the bottom of the valves. That means the oil enters the combustion chamber and burns away.

How to change engine oil?

Bike engine oil must be changed as recommended in the owner’s manual. A step-by-step process is mentioned in all service manuals and can be done at home. Make sure you have the right tools to get the procedure done. The bike must be in the center stand while changing the oil. Use the paddock stand if the center stand is not there for the motorcycle.

The general steps for a bike engine oil change are as follows:

  1. Keep all tools ready as mentioned in the manual
  2. Drain used oil in the oil pan
  3. Replace with new oil filter if needed
  4. Pour in the new engine oil using the funnel.
  5. Check all nuts and screws for tightness. Be careful not to overtighten it, as it might lose the thread.

How to fix an oil leak in a motorcycle?

A motorcycle engine oil leak is not a DIY task and should be handled by a technician. If an engine oil leak is there, turn off the motorcycle immediately and tell the technician about it. Coordinate the rest of the steps with the technician, and nowadays, several companies offer roadside assistance, like Royal Enfield, which is a great initiative.

Which bike engine oil is the best in India?

Here, we are not recommending individual engine oil because engine oil type varies among models, but instead, we are suggesting some of the best brands, and they are

  1. Motul
  2. Shell
  3. Polaris
  4. Castrol
  5. Liqui Moly
  6. GULF Pride
  7. HP Lubricants

Does motorcycle engine oil expire?

Yes, motorcycle engine oil does expire, but it’s not like food where it goes bad overnight. The expiration date on the oil container is not necessarily an indication of when the oil is no longer usable.

Here’s what you need to know about motorcycle engine oil expiration:

Unopened Oil:

  • Conventional oil: Generally has a shelf life of 2-5 years.
  • Synthetic oil: Can last up to 10 years when stored unopened in a cool, dry place.

Opened Oil:

  • Once the container is opened, the oil starts to degrade due to exposure to air and moisture.
  • It’s recommended to use opened oil within 1-2 years.


In this article, we have discussed almost all topics related to motorcycle engine oil.

If you have any other doubts or queries, email us at bikeleague2017@gmail.com. We are always eager to help and assist you. Also, here are several social media platforms of Bikeleague India to raise your suspicions.

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