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The Best Oil for M8 Harley Engines Gets Revealed (Complete)

Chase Manhattan Avatar

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Is your Harley’s powerful M8 engine not delivering optimal performance? Are you unsure about which oil can truly awaken the beast within your sleek, heavy-duty ride? The search ends here, as we embark on an in-depth dive into the world of top-quality oils ideally suited for M8 Harley engines. Lubrication is tantamount to life for your M8 engine, playing the twin roles of protector and enhancer, reducing friction and thus, wear and tear, whilst also improving throttle response. But not just any oil can serve this Herculean role. It should also match the engine’s distinctive requirements, be durable, heat-tolerant and sustain a high performance environment. In this comprehensive guide, we reveal the best oil for M8 Harley engines, providing an enlightened pathway towards maximum engine proficiency. Get ready to experience your Harley just the way it was meant to be – raw, roaring and relentlessly powerful. Keep moving and let’s get to it!

  • Chase’s Oil Pick
    This is the second picture of the Amsoil synthetic V-Twin oil.

    Amsoil 20w50 Full Synthetic

    – Enhanced Engine Protection
    – High-Temperature Stability
    – Wet Clutch Compatibility

  • Chase’s Filter Pick
    This is a second picture of the K&N KN171b Oil Filter for Harley Davidsons.

    K&N 171b

    – High-Efficiency Filtration
    – Durable Construction
    – Easy Installation


Why Oil Matters

Your motorcycle’s engine oil serves several crucial functions. It lubricates moving parts, reducing friction and wear. It also protects against corrosion, helps cool the engine, and assists in maintaining engine cleanliness by minimizing the deposit of harmful substances. Therefore, the importance of choosing the right oil for your Harley Davidson M8 cannot be overstated.

Synthetic vs Conventional Oil

When it comes to the best oil for M8 Harley, you’ll likely encounter a debate between synthetic and conventional oils. Synthetic oils, created through complex chemical reactions, offer superior performance and protection. They withstand high temperatures better, flow more efficiently in cold weather, and generally provide better engine protection.

On the other hand, conventional oils, derived directly from crude oil, might be less expensive, but they might not provide the same level of protection as synthetic oils, especially under extreme conditions.

Top Choice: Synthetic Oil

Among synthetic oils, one brand that consistently receives high praise in the Harley community is Amsoil 20-50 for V-Twins. This oil is specifically formulated for the unique requirements of air-cooled V-twin engines, making it a top contender for the best engine oil for Harley M8 engines.

This is the second picture of the Amsoil synthetic V-Twin oil.

Amsoil 20w50 Full Synthetic


Key Features

  • Enhanced Engine Protection: Amsoil 20W-50’s robust formulation provides superior wear protection, safeguarding your M8 engine’s critical components even under extreme conditions.
  • High-Temperature Stability: This oil maintains its protective qualities in high heat, ensuring consistent engine performance and safeguarding against oil breakdown.
  • Wet Clutch Compatibility: Specifically designed for V-twin engines, it offers optimal clutch performance, essential for the smooth operation of your Harley’s transmission.

Warranty Concerns

You might wonder what the implications of switching to a different oil brand, such as Amsoil, might be on your Harley Davidson warranty. Generally, warranties cannot be voided solely based on the brand of oil used. As long as the oil meets the specifications outlined in your owner’s manual, your warranty should remain valid.

Riding Conditions and Oil Choice

Your riding conditions and habits should also influence your oil choice. If you use your Harley for daily commuting, long-distance rides, or exploring backwoods roads, a high-quality synthetic oil like Amsoil 20-50 would be a suitable choice. It’s designed to provide superior protection under a wide range of conditions, making it ideal for all-season use.

Best Oil Filter Choices

When changing your engine oil, replacing the oil filter is also recommended. Some top oil filter choices among Harley riders include those produced by Twin Power, K&N, and Mobil 1. These filters are highly rated for their construction quality, filtration performance, and durability.

This is an exmaple of the K&N KN171b Oil Filter for Harley Davidsons.

K&N171b Oil Filter


Key Features

  • High-Efficiency Filtration: The K&N171B is engineered for superior filtration, efficiently removing contaminants to protect your engine.
  • Durable Construction: Designed with a heavy-duty metal casing, it offers exceptional durability and is built to withstand the rigors of motorcycle riding.
  • Easy Installation: Features a pre-drilled hole for safety wire attachment, making it user-friendly and easy to install on your Harley

The Importance of Regular Oil Changes

No matter what oil you choose, regular oil changes are critical. Over time, engine oil breaks down and can become contaminated with dirt, metal shavings, and other debris. Regular oil changes ensure that your engine is always lubricated with fresh, clean oil, which can significantly prolong its life.

More Tips for “Babying” Your Engine

In addition to using the best oil for Harley Davidson M8, there are other ways to take good care of your engine. Regular maintenance, using high-quality fuel, and keeping your bike in optimal running condition can also contribute to engine longevity.

By the way, have you heard about the substantial gains from the M8 engine when appropriately tuned? If not, I suggest you check it out: The Best Tuner For Milwaukee 8 114 Engines (+Alternatives)

Conclusion

Choosing the best oil for your Harley Davidson M8 is crucial to ensure optimal engine performance and longevity. While many options exist, synthetic oils, like Amsoil 20-50, are often recommended due to their superior protective qualities. However, always consider your personal riding habits and conditions when making your choice. Regular oil changes and maintenance, along with the use of high-quality oil filters, will also contribute to keeping your M8 engine purring for years to come.


What oil goes in a Harley M8?

For Harley-Davidson motorcycles with the Milwaukee-Eight (M8) engine, it’s recommended to use 20W-50 motorcycle oil. Harley-Davidson produces its own specific oil for these engines, but other high-quality motorcycle oils that meet the same specifications can also be used.

What oil does Harley recommend?

Harley-Davidson generally recommends using their own brand of motorcycle oils. For most of their engines, including the newer models, 20W-50 motorcycle oil is often suggested. Harley’s specific oil formulations are designed to meet the unique demands of their motorcycle engines.

Should I use synthetic or regular oil in my Harley?

The decision to use synthetic or regular oil in a Harley-Davidson motorcycle depends on several factors, including the specific model, riding conditions, and personal preference. Synthetic oil typically offers better performance, especially in extreme temperatures, and may extend the time between oil changes. However, some older models may run better on regular, mineral-based oils.

Can you mix synthetic and regular oil in a Harley?

Technically, you can mix synthetic and regular (conventional) oil in a Harley. Modern oils are generally compatible with each other. However, mixing different types of oil can dilute the performance benefits of synthetic oil. It’s generally best to use one type of oil consistently to maintain optimal engine performance and longevity.