5 Best Engine Oil for 4-Stroke Dirt Bikes

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Dirt bike oils are not made equal, as a four-stroke engine has more demands due to its inherent design.

During racing, for example, temperatures in the engine of a 4-stroke dirt bike can reach as high as 265 °F. High-quality oils are also necessary to lubricate parts like the clutch and valve train.

1. Castrol Power1 4T 10W-40 Engine Oil

The Castrol 10W-40 synthetic oil is popular among motorcyclists with 4-stroke dirt bikes. It has clear emissions since it is fully-synthetic, and it will suit riders who want green solutions for their bikes. It also meets emission standards required by API SL

The oil is ideal for people who want to get top speeds and acceleration with racing bikes. Jerky starts will be a thing of the past with this specialized oil from Castrol as it is designed especially for speedy motorcycles.

It is also quite versatile, and it works in fuel-injected and carburetor engines. The oil provides exceptional motor performance for demanding bikes, and it will especially work well with motorcycles equipped with turbochargers.

The Castrol 10W-40 motorcycle oil is formulated using sophisticated technologies like the Trizone technology to protect the clutch, engine, and gearbox.

Your motor will be spared of premature corrosion as the oil discourages the accumulation of carbon deposits, sludge, and lacquer. Gear switching will be smooth because the oil enhances clutch slip control.

The oil maintains viscosity even in extreme conditions. In the case of mechanical stress, the oil will not thin out or change the state, and you can expect consistent performance in different circumstances.

The Castrol 10W-40 exceeds JASO MA-2 specifications, and it will work seamlessly with European and Japanese dirt bikes. The oil is a great value pick if you want to get the most performance out of your 4-stroke dirt bike.


2. Valvoline 4-Stroke SAE 10W-40 Engine Oil

This oil contains proprietary formulations of premium base oils and superior additive technology to help riders get maximum performance from their motorcycles.

It is packed with shear-stable viscosity improvers that resist oil film breakdown, and the oil will remain liquid even in high temperatures.

The oil will maintain proper lubrication while its optimal friction capabilities will protect the wet clutch and promote smooth shifting.

It is also blended with special cleaning agents that keep motors clean and prevent deposit accumulation.

Your engine will, therefore, be well protected from corrosion. The Valvoline 4-stroke motor oil has silicone additives that maintain the required lubricating film by preventing foaming.


3. Maxima Premium4 10W-40 Engine Oil

The Maxima multi-grade 4-stroke oil is impressively stable and promises a long life in your bike’s engine. It is formulated with additional anti-scuff additives to handle high temperatures and extreme loads in high-performance motors.

The oil’s petroleum base has been blended with anti-wear and anti-shear additives. You can expect optimal performance even when your bike is under mechanical stress.

This oil works well with both water- and air-cooled engines. Maxima recommends it for a wet clutch, and you can enjoy a smooth start when you power your motor.

It will especially suit young riders or riders who don’t do a lot of maintenance on their bike. The oil will stay clean for a long time, during which you will continue to experience superior performance.


4. Quicksilver SAE 10W-30 Engine Oil

The Quicksilver marine engine oil features a high-grade blend of synthetic and mineral-based stocks. You get superior engine corrosion protection as well as premium viscosity retention.

You don’t have to worry about the oil changing state as you race on the track.

The Quicksilver 4-stroke marine engine oil is a result of more than five years of research, testing, and development, and you can be confident that you are getting a quality product.


5. Kawasaki 4-Stroke SAE 10W-40 Engine Oil

The Kawasaki 4-stroke motorcycle engine oil promises extended motor life through enhanced engine cleanliness. Dirt riders commonly face the loss of vitality in their engine oils when maintaining their dirt bikes.

Kawasaki has designed its engine oil to maintain viscosity and improve engine performance. Its lubrication properties also promote noise-free transmission and smoother gear shifting.


10w40 vs 5w40 – Which is Best for Your 4 Stroke Dirt Bike?

Engine oils can get confusing because of the different kinds in the market. You may have also heard that the wrong engine oil can harm your bike’s functionality, and you are therefore keen on getting the right kind.

You have probably seen oils rated 10W-40, where the first number represents 10 °C, and ‘W’ stands for winter. Such oil will work appropriately at the determined temperature during winter.

The second number indicates how thick the oil gets under the heat of a running motor. The higher the indication, the thicker the oil will get under heat.

Oils specified as 10W-40 are only designed for motorcycles, and they protect the transmission, engine, and clutch. The excellent viscosity of these oils enables them to protect the engine in a range of riding conditions.

10W-40 oil also lubricates the internal parts and maximizes the engine’s performance. 5W-40 oils, on the other hand, are used for multiple high-mileage engines like race cars.

Whant to know what is the difference between 10w30 and 5w30, then check out my other article.

Why do You Need to Change Oil on a Dirt Bike?

Engine oil collects the byproducts of your motor’s combustion. External pollutants also get in the oil via the air filter, which is why you need to change your bike’s oil regularly.

How Often do You Need to Change the Oil on Dirt Bike?

Oil changes should be done every five to 10 hours, as per the manufacturer’s recommendations.

How Much Oil Does Your Dirt Bike Need?

Most bikes hold between 600-800ml in the crankcase. The volume of oil is, however, dependent on the make, model, and year of your dirt bike.

Can You Use 2-stroke Engine Oil in a 4-Stroke engine?

Four-stroke engines work under high operating temperatures. They need oils with a high viscosity to support performance even in fast racing conditions. The properties of 2-stroke oils cannot handle these working conditions in a 4-stroke engine.


4-stroke dirt bikes are much faster than before, thanks to advancements in technology.

You will need high-grade four-stroke oils for your dirt bike if you expect superior performance from your motorcycle. Look for reputable brands in the dirt bike market like Castrol, Maxima, Valvoline, Kawasaki, and Quicksilver.

Josh Berry - MotoShark Editor
Josh Berry
I'm a off-road enthusiast, extreme sport fan and the editor of MotoShark. If you have any questions or suggestions regarding this article, please leave a comment or contact me.

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