Motorcycle engine oil: how to choose the right one?

Proper engine oil is essential for the smooth and long-lasting operation of a motorcycle engine. It reduces friction between moving parts, helps control temperature, protects against wear, and helps keep the engine interior clean.

However, there are many different oils available in stores – 10W-40, 10W-50, 15W-50, mineral, semi-synthetic, synthetic, JASO MA or MA2.

Therefore, the most important question is not "which oil is best?", but which oil the manufacturer specifies for a particular motorcycle.

What does oil do in a motorcycle engine?

Engine oil performs several functions simultaneously.

It:

• lubricates moving engine parts;
• reduces friction and wear;
• helps dissipate heat;
• helps protect metal surfaces from corrosion;
• collects some combustion and wear products;
• helps maintain engine cleanliness.

In many motorcycles, the same oil is also used in the engine, gearbox, and wet clutch systems. For this reason, motorcycle oil may have different requirements than regular car engine oil.

What oil should be put in a motorcycle?

First, check your motorcycle's owner's or service manual.

In it, the manufacturer usually specifies:

• the recommended SAE viscosity grade;
• the required API or other specification;
• the JASO class, if applicable;
• the required amount of oil;
• the oil change interval.

If the manual specifies a particular specification, it is important to adhere to it when choosing oil.

The mere fact that two oils are labeled 10W-40 does not mean that both are equally suitable for a particular motorcycle.

What does 10W-40 mean?

One of the most common markings seen on oil packaging is, for example:

10W-40

This is an SAE viscosity grade.

Simplified:

10W describes the oil's behavior at low temperatures. The letter W stands for "winter."

40 describes the oil's viscosity grade when the engine reaches higher operating temperatures.

The smaller the first number, the more suitable the oil is for flowing at lower temperatures according to the requirements of the corresponding SAE class.

However, this does not mean that you should arbitrarily choose smaller or larger numbers.

Use the viscosity grade recommended by the manufacturer for your specific motorcycle or the permitted range.

10W-40 or 10W-50?

A common mistake here is thinking that a higher second number automatically means "better" oil.

This is not the case.

10W-40 and 10W-50 have different high-temperature viscosity characteristics, but the correct choice depends on the specific engine design and manufacturer's requirements.

If the motorcycle manufacturer specifies 10W-40, you should not arbitrarily pour in 10W-50 just because it seems "stronger."

For some motorcycles and operating temperatures, the manufacturer may allow several different viscosity grades. In this case, follow the table or recommendations provided in the manual.

What do JASO MA and MA2 mean?

When choosing oil for a four-stroke motorcycle, you often see:

JASO MA
or
JASO MA2

These classifications are particularly relevant for motorcycles using a wet clutch, meaning the clutch operates in the same oil.

Car oils may contain friction modifiers that are not necessarily suitable for the operation of a specific motorcycle's wet clutch.

JASO MA and MA2 specifications define the oil's friction characteristics relevant to such motorcycle systems.

If the motorcycle manufacturer requires JASO MA or MA2, choose the appropriate oil.

What is the difference between JASO MA and MA2?

Both classes are for four-stroke motorcycle oils, but their friction characteristic limits differ.

Class MA2 sets more specific higher friction characteristic limits in certain clutch test areas.

However, this should not lead to the conclusion that MA2 is always better than MA.

The most important thing is what the motorcycle manufacturer specifies for a particular engine and clutch system.

Mineral, semi-synthetic or synthetic oil?

Based on the type of base oil and final formulation, three general categories are most commonly found on the market.

Mineral oil

Mineral oils are made using refined petroleum base oils and appropriate additives.

They can be used in motorcycles for which such oil is suitable according to the manufacturer's specification.

This is often a more economical choice, but it should not be assumed that mineral oil is automatically suitable for every older motorcycle.

Semi-synthetic oil

Semi-synthetic oil uses a combination of mineral and synthetic base components.

It is often chosen as a compromise between price and performance.

However, here too, the most important thing is not the label "semi-synthetic," but compliance with the motorcycle manufacturer's required specifications.

Synthetic oil

Synthetic oil formulations are developed using synthetic base components and additive packages.

They often exhibit good high-temperature stability and are used in modern, higher-stress engines.

However, the most expensive fully synthetic oil is not automatically the best choice for every motorcycle.

If the manufacturer specifies different requirements, they must be followed.

Can car oil be used in a motorcycle?

It is not possible to answer simply "never", but you should not choose car oil without checking the motorcycle manufacturer's requirements.

In many motorcycles, the engine, transmission, and wet clutch use the same oil. Such a system requires oil to meet specific requirements that a particular car oil may not meet.

Therefore, it is most practical to choose an oil whose specifications clearly match the motorcycle manufacturer's instructions.

Two-stroke and four-stroke motorcycle oil are not the same

Here the difference is fundamental.

Four-stroke engine oil circulates in the lubrication system and is changed periodically.

In two-stroke engines, special 2T oil usually participates in the combustion process – depending on the design, it can be supplied by a separate lubrication system or mixed with fuel.

Therefore, 2T and 4T oils cannot be considered interchangeable products.

Always use the oil specified for your particular engine.

Can different motorcycle oils be mixed?

In an emergency, it is more important to ensure proper oil level than to ride with dangerously low oil levels.

However, regularly mixing oils of different specifications, viscosities, or purposes is not a good strategy.

If you need to top up, it is best to use the same oil or an oil that meets the manufacturer's requirements.

If you don't know what is currently in your motorcycle, a safer solution might be a complete oil change and, when specified, a filter change.

How much oil does a motorcycle need?

There is no single answer.

The required amount depends on:

• the motorcycle model;
• the engine;
• whether the oil filter is being changed;
• the specific maintenance procedure.

The manufacturer's manual may specify several different oil quantities for different situations.

Therefore, do not pour an arbitrary amount based solely on the engine's displacement.

When to change motorcycle oil?

The oil change interval is set by the motorcycle manufacturer.

It can be defined by:

• kilometers traveled;
• time elapsed;
• both criteria.

When operating a motorcycle in difficult conditions, more frequent maintenance may be required.

Therefore, the universal rule "change every 5000 km" is not suitable for all motorcycles.

Should the oil filter be changed at the same time?

The oil filter change interval is also set by the manufacturer.

In many motorcycles, the filter is changed along with the oil or according to a separate maintenance schedule.

Use a filter suitable for your specific motorcycle model.

How to check motorcycle oil level?

The procedure varies depending on the motorcycle.

The oil level can be checked:

• through a sight glass;
• with a dipstick;
• electronically.

The required motorcycle position, engine temperature, and the time to wait after switching off the engine may also differ.

Therefore, when checking the oil level, follow the specific motorcycle manual.

Too little oil can damage the engine, but too much oil is also not appropriate.

How to choose motorcycle oil? Briefly

Before buying, check four things:

1. SAE viscosity
For example, 10W-40.

2. Required specification
For example, the API class specified by the manufacturer.

3. JASO class
If the manufacturer requires MA or MA2.

4. Motorcycle manufacturer's recommendations
These are more important than general internet advice.

If all requirements match, then you can compare manufacturers, price, and specific product lines.

Motorcycle engine oil TMOTO

At TMOTO, you will find motorcycle engine oils of different viscosity grades and specifications, as well as oil filters and other motorcycle maintenance products.

If you don't know what oil is suitable for your motorcycle, contact us or visit the TMOTO store in Kaunas. We will help you choose the right option according to your motorcycle model and manufacturer's requirements.