The Ultimate Guide to Harley Oil: Choosing the Best for Your Motorcycle

If you own a Harley-Davidson motorcycle, you know how essential it is to maintain its performance and longevity.

One crucial aspect of motorcycle maintenance is choosing the right oil.

This comprehensive guide will explore everything you need to know about Harley oil, from its importance to selecting the best option for your bike.

So, let’s dive in and ensure your Harley runs at its peak!

Harley Oil

Why is Choosing the Right Oil Important?

Selecting the right oil for your Harley is vital to keep the engine running smoothly and efficiently.

The engine’s performance heavily relies on the oil’s ability to lubricate, cool, and protect its intricate components.

Proper lubrication reduces friction, minimizing wear and tear and increasing engine life.

Understanding Viscosity: What do those Numbers Mean?

You’ll notice numbers like 20W-50 or 10W-40 when you explore various oil options.

These numbers represent the oil’s viscosity, which indicates its thickness and flow properties.

The “W” stands for winter, and the number preceding it indicates how well the oil flows at lower temperatures.

The second number represents the oil’s viscosity at operating temperatures.

For most Harley-Davidson motorcycles, the recommended viscosity is 20W-50.

This oil provides excellent lubrication and stability across various temperatures, ensuring optimal performance in both cold and hot climates.

Synthetic vs. Conventional Oil: Which is Better for Your Harley?

The debate between synthetic and conventional oil has been ongoing for years.

Synthetic oil is artificially made in a lab, offering superior performance and protection due to its uniform molecular structure.

On the other hand, conventional oil is derived from crude oil and contains impurities that may lead to more rapid breakdown under extreme conditions.

For Harley-Davidson motorcycles, synthetic oil is generally the better choice.

Its exceptional properties help reduce engine heat, resist oxidation, and maintain stability over extended oil change intervals.

Synthetic oil ensures your Harley remains in top condition, even during demanding rides and harsh weather conditions.

Harley Oil

The Role of Additives in Harley Oil

Many oils on the market have additives that enhance their performance and protection.

Some common additives found in high-quality Harley oil include:

1. Detergents

Detergents help keep the engine clean by preventing the build-up of sludge and deposits.

A clean engine performs better and has an extended lifespan.

2. Dispersants

Dispersants work hand in hand with detergents to suspend contaminants, preventing them from settling and causing harm to the engine.

3. Anti-Wear Additives

As the name suggests, anti-wear additives form a protective layer on engine components, reducing friction and minimizing wear on vital parts.

4. Viscosity Index Improvers

Viscosity index improvers help the oil maintain its thickness and stability across a wide temperature range.

Harley Oil

Selecting the Right Harley Oil for Your Motorcycle

Choosing the best oil for your Harley can be overwhelming, with numerous options available.

Here are some essential factors to consider:

1. Harley’s Recommended Oil

Always start by checking the owner’s manual or the manufacturer’s website for the recommended oil for your specific Harley model.

Using the manufacturer-recommended oil ensures you are meeting the necessary specifications and requirements.

2. Viscosity Grade

As mentioned earlier, Harley-Davidson typically recommends 20W-50 viscosity grade oil.

However, if you live in a frigid climate, you may consider a 10W-40 oil for easier starting in frigid temperatures.

3. Synthetic Oil Benefits

If your budget allows, opt for synthetic oil.

The advantages it offers in terms of performance, protection, and extended oil change intervals make it a worthwhile investment.

4. Additives

Consider whether you want specific additives like extra detergents or anti-wear properties, depending on your riding style and the conditions you encounter.

5. Brand Reputation

Choose reputable brands with a proven track record of producing high-quality motorcycle oils.

Well-established brands often have extensive research and development behind their products, ensuring top-notch performance.

Harley Oil

Changing Your Harley Oil: Step-by-Step Guide

Now that you’ve selected the perfect oil for your Harley let’s go through the oil change process step-by-step:

Gather the necessary tools and materials: Harley oil filter, wrench, drain pan, and funnel.

Warm up the engine: Run your motorcycle for a few minutes to warm up the oil, making it easier to drain.

Locate the drain plug and oil filter: Refer to your owner’s manual to find the drain plug and oil filter location.

Drain the old oil: Place the drain pan beneath the drain plug and remove it to let the old oil flow out. Once drained, replace the drain plug.

Change the oil filter: Unscrew the old oil filter and replace it with a new one. Apply a bit of new oil to the gasket before installing the new filter.

Add the new oil: Use a funnel to pour the new oil into the oil tank, following the recommended quantity from your owner’s manual.

Check the oil level: Start the engine and let it idle for a minute.

Turn off the engine and check the oil level using the dipstick. Add more oil if necessary.

Dispose of the old oil responsibly: Take the used oil and filter to a recycling center or an authorized disposal facility.

AMSOIL Synthetic Motorcycle Oil vs. Harley Davidson Motor Oil


Selecting the right Harley oil is essential for your motorcycle’s optimal performance and longevity.

Stick to the manufacturer’s recommendations and choose a high-quality synthetic oil if possible.


Q. What type of oil should I use in my Harley?
For your Harley-Davidson motorcycle, it is recommended to use high-quality motorcycle oil that matches the manufacturer's specifications. Typically, Harley-Davidson suggests using 20W-50 viscosity grade oil, which provides excellent lubrication and stability across various temperature ranges. Using the right type of oil ensures optimal engine performance and longevity.

Q. Do Harleys need special oil?
Harleys do not necessarily require "special" oil, but they do benefit from using high-quality motorcycle oil designed for their specific needs. Standard automobile oils might not offer the same level of protection and performance that motorcycle oils provide. Therefore, it is crucial to use oil specifically formulated for motorcycles, particularly for air-cooled engines like those found in most Harley-Davidson models.

Q. What weight motor oil do you put in a Harley-Davidson?
Harley-Davidson recommends using 20W-50 viscosity grade oil for most motorcycle models. This weight is suitable for providing proper lubrication and protection across a wide range of temperatures, making it ideal for various riding conditions.

However, in extremely cold climates, you may consider using a lighter oil, such as 10W-40, to ensure easier starting and better flow in low temperatures. Always check your owner's manual or consult the manufacturer's recommendations for the exact weight of oil suitable for your specific Harley model.

Q. Is synthetic oil better for Harleys?
Yes, synthetic oil is generally considered better for Harley-Davidson motorcycles. Synthetic oils are engineered to provide superior performance, protection, and stability, making them an excellent choice for high-performance engines like those in Harleys.

The benefits of synthetic oil include:
- Reduced engine heat: Synthetic oil's advanced formula helps dissipate heat more effectively, preventing overheating and potential engine damage.
- Enhanced lubrication: Synthetic oil's uniform molecular structure provides better lubrication, reducing friction and wear on engine components.
- Longer oil change intervals: Synthetic oil typically lasts longer than conventional oil, allowing you to go for more extended periods between oil changes.
- Improved cold start performance: Synthetic oil flows more smoothly in cold temperatures, ensuring easier starts even in frigid weather conditions.