What Does Motorcycle Oil Actually Do? (And Why It Needs to Be Changed)

We all know that a motorcycle engine needs oil. But do you know what motorcycle oil actually does and why you need to change it?

The oil in your motorcycle lubricates the parts to eliminate their metal-to-metal contact, takes the heat from the parts, keeps the parts clean, takes the metal and carbon particles and other contaminants to the filter, all of which helps gives you a smooth ride and a better performing engine.

The oil gets heated when the engine is running and gets cooled when the motorcycle is parked.

Due to repeated cycles of heating and cooling, the oil deteriorates over a period, loses its viscosity, and becomes dirty.

The oil in this degraded state cannot do its functions to protect the engine.

If you do not change the oil at this point, the engine parts can get damaged leading to costly repair and replacement. That’s why regularly scheduled oil changes are important to prolong the life of your engine.

We’ll discuss more on this below.

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What does Motorcycle Oil do?

Motorcycle oil has plenty of work to do to ensure a smooth ride and properly functioning engine. Check it out.

Good oil ensures there is always a thin film of oil between two mating surfaces to eliminate metal-to-metal contact (friction) and reduce wear. Examples of parts that come in contact include crankshaft bearings, pistons, cylinders, gears, chains, etc.

The engine oil has detergent additives that attract the carbon particles and contaminants, make them float, and help filter them out.

By doing this, the oil keeps the engine parts clean and reduces sludge formation.

Detergent additives do not allow the contaminants to stick to the engine parts. The detergents keep the oil passages clean and enable proper circulation and flow of oil throughout the engine.

Modern motorcycle engines generate more heat due to higher rpms. The engine oil reduces the frictional heat by ensuring a thin film on all the engine parts.

Furthermore, the engine oil absorbs the heat from the moving parts and dissipates it to relatively cool areas like the oil sump. This helps the engine maintain a safe operating temperature.

The thin film of oil between the surfaces of the piston ring and the cylinder work as a dynamic seal and assists the piston rings to stop the entry of exhaust gasses into the oil sump or entry of oil into the combustion chamber.

The oil film on the engine parts also act as a dampener and helps them to absorb sudden mechanical shocks and increase the life of the parts.

Additionally, the presence of oil in the engine and transmission protects the engine and transmission parts from corrosion.

Why does oil need to be changed?

Oil must have certain qualities to do the above functions efficiently.

These qualities are viscosity and retention of additives in the oil.

As the oil gets heated and cooled over the course of multiple running/parking cycles, the qualities of the oil change.

Due to repeated cycles of heating and cooling, the oil deteriorates over a period, loses its viscosity, and becomes dirty. There can be a slight reduction in oil quantity also. 

When this happens, it needs to be drained and replaced with new oil.

Not changing the oil at this stage can cause damage to the motorcycle parts leading to costly repair and replacement.

Bad oil cannot perform its functions and can lead to an increase in engine operating temperature, which can also cause damage to the engine.

Good oil gives you a smoother ride, and the converse is also equally true. If the oil is bad, shifting and gear changes can make a lot of noise.

To ensure the efficient and safe operation of your motorcycle, a regular oil change is important.

When we talk about oil changes, we normally refer to the engine oil, but the transmission and primary of your motorcycle also use oil for lubrication. So, the term oil change in motorcycles broadly includes the engine oil and the lubricant for transmission and primary.

In the case of a shaft-drive motorcycle, you have one more place to change the oil. Also, it is good to change the oil filter when you change the engine oil.

Types of Motorcycle Oil

The oil used in a motorcycle can be classified into three categories:

  • Mineral oil/conventional oil.
  • Semi-synthetic oil.
  • Synthetic oil.

Mineral/Conventional Oil

Conventional oil is one of the products produced during the refining of crude oil, and this oil is used in older motorcycles that operate at lower temperatures.

It is generally not suitable for modern high-powered motorcycles because of their very high operating temperature.

Mineral oil will lose its lubricating property fast and gets deteriorated and it needs faster oil changes.

Semi-synthetic Oil

Semi-synthetic oil is a blend of conventional oil and synthetic chemicals.

It possesses some benefits of both oil types. This type of oil typically performs better than conventional oil and is used in mid-range motorcycles.

Synthetic Oil

Synthetic oils are developed through research and development.

It is a combination of different chemical compounds (modified petrochemicals) blended together. They are produced by combining various chemical compounds to meet the quality needs and specific applications for the engines that they’re designed for.

The components of the synthetic oil can differ to meet the needs of modern, high-performance motorcycles. Synthetic oil is typically more expensive than conventional and semi-synthetic oils.

Synthetic oil contains additives like detergents. These additives attracts the impurities like dirt, debris, and carbon particles, make them float, and takes them to the filter for filtering out. The detergent additive does not allow the formation of sludge and improves the life of the synthetic oil.

Synthetic oil has a better lifespan, and does not deteriorate nor break down as fast. Most of the high-performance motorcycles of today recommend synthetic oils.

Oil Grades

You might have come across oil designations like SAE 10 W-40, SAE 20 W-50, etc.

These designations are as per the SAE (Society of Automotive Engineers, based in the USA).

In SAE 10W – 40, “W” stands for winter and it means the oil can be used in winter conditions.

The number 10 (before the “W”) signifies the viscosity of the oil at low ambient temperatures (before you start the engine).

If you refer to the SAE chart, 10 refers to a temperature of -25° C (-13° F) and this means the oil can retain its viscosity or flow ability at a minimum ambient temperature of -25° C (-13° F).

The number 40 (after “W”) indicates the capability of the oil to retain its viscosity at a maximum ambient temperature of 40 ° C (104° F).

Oil ratings like SAE 10W-40 are called multi-rated oils and have additives that do not allow the oil to thicken at cold temperatures.

Oil Changes

Your owner’s manual may recommend the first oil change for all the oils (engine, transmission, and primary) after the first 1,000 miles. Subsequent oil change frequency will be different.

The frequency of engine oil and filter change is generally every 2,000 to 5,000 miles. You can find the oil change recommendations for transmission and primary in the owner’s manual. Be sure to follow the schedule of oil changes recommended in the owner’s manual.

However, the above applies to motorcycles that are in regular use.

If your motorcycle is parked for a longer period, it is smart to inspect the oil quality before you ride and change the oil if necessary.

If your place has extreme weather, you may have to inspect the oil in your motorcycle more frequently and the oil change may be required well before the recommended schedule.

When you do change your oil, be sure to replace it with the same type. You can learn more about that topic here: Can you mix different brands of oil?

The oil in your engine attracts the contaminants, make them float, and moves them to the filter to take out the dirt. This process happens repeatedly and makes the filter dirty and useless after some time.

To keep up the efficiency of the engine oil it is recommended to change the oil filter along with the oil change.

If you are regularly riding your motorcycle in a dusty environment, the oil filter may need more frequent replacements.

Oil plays an important role in your motorcycle and you are assured of a safe and smooth ride by following the recommended oil change schedules. Happy riding.

Learn more about how to change your motorcycle oil here.