Motorcycle Engine Oil: Choosing Without Being Wrong

Conseils pour choisir sans se tromper l'huile moteur moto.

How to choose the best engine oil?

For a recent motorcycle, the easiest way is to follow the manufacturer's recommendations, adjusting the viscosity if necessary according to the conditions of use (intensity, geographical location). The question will arise more for old motorcycles, used as a basis for preparing Café racers, whose year of commissioning, brand or even mileage require the selection of an appropriate oil.

Mineral, semi-synthetic or synthetic, monograde or multigrade, viscosity, API and JASO standards, here is a complete point on the specificities of motorcycle engine oil to help you choose without risk of making a mistake.


What is engine oil used for?

Essential to the operation of the engine, the oil lubricates each of its component parts. It coats them with a protective film whose properties reduce the wear caused by the friction of moving metal parts and guarantees the tightness of the segmentation and the valve seats.

It also contributes to the cooling of parts subjected to the very high temperatures generated by the combustion chamber and the piston.

Oil temperature gauge.

Other roles of engine oil: protect against corrosion, maintain and maintain engine performance by filtering dust, residue and impurities accumulated over the miles.

This is why, in order to preserve your motorcycle and ensure its proper functioning, it is recommended to:

  • drain once a year, to be adapted according to use (sports) or the number of kilometers traveled (> 6,000 km);
  • check the oil level and its color;
  • add the recommended amount of oil, no less no more.

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Classification of oils: SAE, API, JASO standards

Society of Automotive Engineers (SAE)

It lists monograde and multigrade engine oils according to their viscosity characteristics. (10W40, 5W30, etc.)

The SAE standard does not define the quality of the oil, only information about its viscosity. It is divided into two categories: “10W” cold start and “40” hot start. The letter W specifies the performance of the oil in the winter period.

American Petroleum Institute (API)

The API distinguishes oils for petrol (S) and diesel (C) engines. The following letter allows you to know the quality of the lubricant, with regard to its year of design. Therefore, the further it is in the alphabet, the more recent it is, and of better quality. “SN” thus indicates an oil of a higher quality than “SM”.

  • 1996: API SJ
  • 2001: API SL
  • 2007: SM API
  • 2010: API SN
  • 2020: API SP

Japanese Automotive Standards Organization (JASO)

It defines the criteria for oils for the engines of two-wheeled vehicles. High demands are placed on the friction behavior for motorcycles with wet clutches, on the shear stability and the attitude of the oil to combustion.

  • 4-stroke engines:
    • MA: for motorcycles with wet clutch;
    • MA 2: for motorcycles with wet clutch gearbox;
    • MB: for motorcycles without wet clutch;
  • 2-stroke engines:
    • FB: weak cleaning, incomplete combustion;
    • FC: high cleaning, almost complete combustion;
    • FD: optimal cleaning, complete combustion.

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Honda motorcycle engine.

The different categories of engine oils

engine oil is a combination of a base and chemical additives. Three bases are to be distinguished: mineral, semi-synthetic and synthetic.

Mineral motor oil

Mineral oil is the oldest and simplest base oil. This so-called conventional oil is obtained from the refining of crude oil (mixture of saturated hydrocarbons).

The crude oil is heated and decomposed by distillation. This is followed by the refining and dewaxing phases to remove the undesirable components (the subsequent addition of specific additives will reduce or eliminate the remaining ones).

Sprinta T100 mineral oil

The final step, hydrofinishing, increases aging stability by supplying the raffinate (refined petroleum product) with hydrogen.

Mineral oil, which is less expensive, clogs up more quickly and is not recommended for engines reaching high operating temperatures. It is more suitable for older motorcycles , air-cooled, engines with separate lubrication (engine, transmission). It can also be used for lapping.

Old motorcycle.

The improved version of mineral oil, hydrocracked mineral oil, although it gains in performance, is not necessarily designed in the laboratory. The term synthetic oil, used by some manufacturers, can therefore lead to confusion.

Note : in winter, when the engine is cold, mineral oil will take longer to become fluid.

Semi-synthetic oil

A mixture of mineral oil and hydrocracked synthetic oil, semi-synthetic oil is chemically modified. More robust than mineral oil and hydrocracked mineral oil, it benefits from superior performance without, however, equaling that of 100% synthetic oils.

Putoline Semi-Synthetic 4T engine oil. semi-synthetic oil 2T Petronal T500

At an intermediate price, it adapts to most motorcycles and to different temperatures.

100% synthetic motor oil

It is made from a complex manufacturing process (recomposition of the chains of naphtha molecules) which makes it a more expensive oil. More homogeneous, benefiting from an excellent lifespan , it offers better resistance to high temperatures. Its higher price is in fact offset by a period of use 2 to 3 times greater than mineral oil.

The 100% synthetic oil guarantees optimal performance thanks in particular to a remarkable thermal stability and a high cleaning capacity (note that it also generates less residual deposits in the engine).

Petronas 4T F900 oil Putoline RS959 engine oil

Temperature variations have little influence on its viscosity and it oxidizes less. Its fluidity allows, at low temperature, to better protect the engine during starting, by reducing friction.

The properties of 100% synthetic oils ideally meet the constraints of competition motorcycles whose engines run at high speeds, above 10,000 rpm (road, sports, motocross).

However, for a motorcycle operating at lower speeds, less than 6000 rpm , it is preferable to direct its choice towards a semi-synthetic oil for best results. Indeed, the 100% synthetic oil adheres strongly to the walls to form a lubricating layer preventing proper cooling of the piston at low revs.

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Monograde and multigrade oils

In order to choose your motorcycle engine oil without making mistakes, it is necessary to distinguish monograde, only mineral engine oils from mineral or synthetic multigrade oils.

Triumph motorcycle engine.

multigrade oil

Improved by the addition, in particular, of additives, multigrade oils offer real versatility in use thanks to good fluidity at low temperature combined with the ability to remain quite thick at high temperature.

Polymer-based additives, contained in multigrade oils, limit the differences in fluidity caused by cold or hot temperatures. They can, unlike monograde oils, be used throughout the year.

When the engine cools down, the oil flows back into the crankcase. When starting the motorcycle from cold, it will take a few microseconds for the oil to spread sufficiently to the parts of the engine that need to be lubricated. Multigrade oils offer the advantage of good fluidity at low temperature , unlike monograde oils.

The engine parts are in fact lubricated from start-up, thus avoiding the risk of premature wear linked to dry friction of moving parts.

motorcycle engine oil.

monograde oil

This type of oil only has a single number by the usual SAE standards. It will thus have either an SAE 40 denomination for hot indication, or SAE 10W for cold indication.

In fact, monograde oil is less versatile and is intended either for summer or winter use. It is up to the user to adapt his oil according to the season of use of the motorcycle.

Mineral oil without additives sees its viscosity change more quickly depending on the temperature. As the engine heats up, the monograde oil will thin out and, conversely, become viscous as it cools.

Hence the need to choose an oil that is more fluid at low temperatures in winter , and to avoid starting with a frozen lubricant. On the contrary, in summer , it is important to benefit from a more viscous oil in order to prevent the alteration of its lubricating properties.

As we have seen, monograde oil being a mineral oil, it benefits from a lower price than a multigrade oil. Its absence of additives makes it particularly suitable for old vehicles such as those without an oil filter.

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chemical additives

Being able to reach 30% of the composition of modern motor oils, the level of additives added to the base oil makes it possible to improve some of its properties or to create new ones (anti-corrosion, antioxidant, detergent, dispersant, etc.) . Others act on the flash point, the pour point or even on the risk of seizing at high pressure.

Two types of additives are to be distinguished:

  • additives operating on the base oil : optimization of pour point, viscosity, antifoam;
  • additives acting on the surface of materials : improvement of adhesion, coefficient of friction.

Which oil properties can be modified with additives?

They are numerous, but among those that can be modulated by the addition of additives can be cited as examples:

  • behavior when cold;
  • resistance to ageing;
  • the relationship between viscosity and temperature;
  • protection against corrosion.

Some characteristics imperatively require the use of additives to be transformed:

  • the dissolution of dirt;
  • the dispersion ;
  • high pressure properties;
  • the defoamer.

Others, on the other hand, cannot be modified by additives:

  • deaeration;
  • water repellency.

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Viscosity index: choosing the right engine oil

Developed by the SAE, the viscosity indices must be respected by the manufacturers of motor oils (5W30, 10W40, etc.).

Namely : the higher the viscosity index, the more stable the viscosity remains over a wide temperature range.

While an oil thickens as it cools , conversely, its viscosity decreases with increasing temperature. However, it must remain viscous enough to maintain a protective film on the engine parts, while remaining liquid enough to circulate properly.

The viscosity index, for example 10W40 is symbolized by two values ​​separated by the letter W (Winter, winter). The “10” preceding the letter W represents the viscosity index, engine cold . The one on the right, “40” indicates the viscosity index of the hot engine .

The closer the number corresponding to the cold viscosity index (value to the left of the W) is to 0, the more the oil will be fluid and suitable for cold starting. Conversely, the higher it is, the more viscous it will be.

Limit temperature for engine oil (the lower the temperature, the thinner the oil should be):

  • SAE 0W: -40°C
  • SAE 5W: -35°C
  • SAE 10W: -30°C
  • SAE 15W: -25°C
  • SAE 20W: -20°C
  • SAE 25W: -15°C

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Adjust the viscosity index to its use

The rule is above all to respect the recommendations of the manufacturer. Then, adjustments can be made according to the geographical location (climate), the use of the motorcycle (sport, performance, tourism, urban), its age, its mileage.

Cold index adjustment

It is essential that the engine oil remains sufficiently fluid to be easily managed by the pump and to effectively protect the moving parts, in particular at the time of a cold start. The outside temperature is in fact an important criterion, especially if your motorcycle spends the night outside, in an area where temperatures are regularly low.

Choose an oil adapted to the cold.

If the 10w40 responds to the temperate climate, it can be replaced by the 5w40 or 5w50 in regions with harsh winters.

Hot index adjustment

In order to meet the requirements of engines reaching high speeds, opt for a hot index of at least 50 or 60 for use in summer when the outside temperature is added to that of the engine.

Adapt your oil to room temperature.

For motorcycles with a high mileage , it may be interesting to increase the index, for example, from 30 to 40, and thus compensate for the play caused by the wear of the parts thanks to a more viscous oil . (Note that abnormal oil consumption may be a sign of the need for an index change.)

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2-stroke and 4-stroke engine oil

In addition to information related to its type and viscosity, the oil must be suitable for 2-stroke (2T) or 4-stroke (4T) engines. The indication 2T or 4T will necessarily be present on the cans.

If in a 2-stroke engine the oil is burned with the fuel, in a 4-stroke engine it remains in the crankcase/parts circuit.

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Motorcycle oil prices at

In our " Fluids and motorcycle maintenance products " section, you will find all the quality engine oils adapted to your motorcycle, as well as specific oils such as Castor R castor oil , specially adapted for the 2T and 4T motorcycles used in Grass Track or Speedway.

Putoline and Petronas oils for 2-stroke engines
2T mineral oil from €10.80
2T semi-synthetic oil €9.90 <> €13.90
2T synthetic oil €10.90 <> €21.90
Putoline and Petronas oils for 4-stroke engines
4T mineral oil from €12.90
4T semi-synthetic oil €11.90 <> €16.90
4T synthetic oil €16.50 <> €19.90

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Choosing a motorcycle engine oil: what to remember

First, follow the manufacturer's recommendations. Then, if necessary, make adjustments according to your driving, your use, your geographical area, the age and the mileage of your machine.

To put it simply, you live in a temperate climate , you ride a standard motorcycle and ride more regularly under 9,000 rpm , opt for a semi-synthetic 10W40 oil . If you are in an area subject to significant temperature drops, switch to 5W40 or 5W50. In summer, index 50 to 60.

For use above 9,000 rpm prefer synthetic oils that will fully meet the performance requirements of the engine.

Finally, if you have an old motorcycle , mineral oil will be the right solution for your engine.

For motorcycles with decent mileage , do not hesitate to raise the viscosity index when hot to facilitate the protection of parts, for example, go from 30 to 40.

You want to learn more, you have questions that our FAQ has not answered, so do not hesitate to contact us via our contact form . We will answer you with pleasure as soon as possible.

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Cafe racer bar.

1 comment

  • Geysse

    Intéressant et pas trop long à lire, accessible pour un bidouilleur. Merci.

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