What is Primary Oil in Harley-Davidson Bikes?


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What Primary Oil For Harley

Are you a Harley-Davidson biker who has a bike in need of oil refilling, but don’t know what primary oil goes into your bike? If yes, then this is definitely the right place for you to be.

What primary oil for Harley-Davidson bikes is a common question that most Harley bikers have. Interestingly, the Amsoil 20W 50 Synthetic Motorcycle Oil for Harley-Davidson is suitable for engine, transmission, and primary oil. These parts of the motorcycle have to withstand constant friction and a lot of pressure. The role of such primary oil is immense when it comes to preventing any internal problems. Some experts also recommend that you could use severe gear 75W 140 for the primary. There is no problem if you use gear oil instead of the 20W 50 option. You must keep in mind that you need to use gear oil and engine oil in specific proportions when using engine oil and gear oil.

In this article, you will get to learn all about primary oil, what primary oil for Harley-Davidson bikes, how to check primary oil, how to change primary oil on a Harley-Davidson bike, and more. Stick around to get all the answers that you are looking for.

What is Primary Oil in Harley-Davidson Bikes?

A motorcycle engine is made up of different motor parts that work in conjunction to convert the fuel energy into mechanical force. In doing so, the different parts of the engine can come in contact and create friction. Routinely, you should regulate engine oil changes, as it’ll be necessary to keep the bike running smoothly.

If you own a Harley-Davidson bike, you must take good care of your bike. Maintenance is important for your motorcycle. You should keep in mind that engine oil isn’t the only maintenance aspect that you should take care of. You have to focus on other things as well. Knowing about the primary chain case and changing the primary oil are also important things to remember if you have a Harley-Davidson bike.

Only engine oil isn’t everything that you require as a lubricant. There are other types of oils too, that lubricate other parts of your bike. Primary oil is a lubricant that is commonly used in the primary chain case for lubricating different components.

The primary chain is the component that takes power from the Harley engine to the wheels. Your primary chain system needs to work smoothly. Primary oil is required for lubricating these parts.

Many motorcycles also use the same lubricant for the transmission, engine, and primary. Most Harley-Davidson bikes make use of different oil sumps for the engine, transmission, and primary chain case. Dealing with primary oil isn’t as complex as some may think. There are a few simple steps that you can take to decide what primary oil for Harley and how to change the oil on your bike.

Importance of Using Primary Oil on a Harley-Davidson Bike

The engine is the heart of your Harley-Davidson bike. To take care of your bike, you should look for the best oil options from reliable brands, but if your bike isn’t maintained well, it could ruin the entire riding experience.

Primary oil is an important lubricant needed for running your Harley. Clean primary oil will help you and your bike from various angles. Here are some of the reasons why it is important to use fresh primary oil in your Harley-Davidson bike – 

  • Lubricate motorcycle components properly as it makes them less friction 
  • It will help you get more mileage and primarily help you utilize the fuel better
  • It will help expand the lifespan of the engine components and your Harley-Davidson bike

How to Change Primary Oil on Your Harley-Davidson Bike

Most Harley-Davidson motorcycles require about 1 quart of oil as primary fluid. Checking the primary fluid on your Harley means that you’ll need to check the condition of the primary oil. Noting the amount of primary fluid on your bike is an important thing to do.

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To check the primary oil, you should set your Harley-Davidson motorcycle upright. After that, remove the primary chain case cover. The fluid will gather at the bottom of the clutch basket. You need to have around 1 quart of fluid there.

Person Putting Primary Oil On A Harley-Davidson Bike

It isn’t that hard if you want to change the primary oil of the Harley-Davidson bike. It is a rather simple task that needs about 15–30 minutes. If you are a Harley-Davidson bike, you need to know how to change the primary oil in your bike. To change the primary oil on your bike, you should follow the steps mentioned below correctly –

1. Gather the necessary tools

First, you will require a few tools that are necessary for the job. Gather these tools so that you can change the primary oil within no time –  a funnel, a torque wrench, a socket wrench, a funnel, a 5/8-inch socket, a new O ring, a primary cover gasket, lubricant oil that is perfect as primary oil.

These tools are basic, and you’ll easily find them in your garage, or you can purchase them at a nearby store if you don’t have them already. Also, keep the owner’s manual nearby. The owner’s manual will give you the necessary information on which tools are the best for changing primary oil.

2. Heat the engine

Before you change the primary oil, you will need to heat the engine. This process will help make the oil smoother. This will help the oil flow relatively quickly. If you’re wondering how long you will have to heat the engine, you must run the bike for around 30 minutes. Once you do that, the primary oil will be smooth enough that it can fall freely.

3. Clean the area

Now, you will have to clean the engine area, especially the drain plug and drained case. You don’t require any washing material to clean these components. You simply have to give it a good wipe using a clean and soft cloth.

4. Find the primary drain plug

Finding the primary drain plug is a necessary process. You need to find the owner’s manual. In the owner’s manual, there is information about where the drain plug is located. If you don’t have a manual, you will find it under the primary drain case. It is like a screw that prevents the primary oil from leaking.

5. Loosen the bolts of the primary drain case

Once you have found the drain plug, you should loosen the bolts of the primary drain case. You should make use of a T-27 torque bit and socket wrench for loosening the bolts of the drain case. Now, you should remove the cover and then keep it aside. Keep the bolts in a safe place, as you’ll need them soon.

6. Drain the fluid

It would be better to wear a pair of protective gloves before draining, as this type of oil can be quite sticky. Now, you should take the 5/8-inch socket and socket wrench for loosening the drain plug. After loosening it, you should place an oil pan below while letting gravity do its work. It could take a few minutes, so you should wait until the last drop of used primary oil is drained.

7. Replace the gasket

It would be better to remove the primary case gasket after each oil change. You need to remove the oil gasket from the case. If you have an issue with the gasket, you should use a new one; otherwise, you can continue using the old one. Now, place the gasket into the case.

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8. Put in the drain plug

Once you have finished these steps, you need to clean the drain plug. After that, you should install the O-ring off the drain plug for making the right sealing. Start off by fitting the plug using your hands and then tighten it with a wrench. Make sure that it is sealed completely.

9. Refill the primary oil

Now, you need to use a funnel to refill the primary oil in your Harley-Davidson bikes. This type of funnel is slightly different from others. Make use of a funnel for filling in the oil in the primary chain case. After that, you should place the cover back before tightening the bolts. Congratulations, you have changed the primary oil.

How Much Primary Oil Goes Into the Bike’s Primary

Harley-Davidson bikes were originally founded back in 1903 in Milwaukee, Wisconsin, USA. The brand manufactures its traditional and iconic heavyweight and air-cooled Cruiser bikes with an engine capacity of over 700cc. For operating this giant machine, you will have to know its oil capacity and ideal oil quality. It cannot be exaggerated, as you will need to be aware of the advantages and disadvantages of primary oil before you choose the right one.

The Harley-Davidson bikes manufactured between 1980 and 2006 have an average initial liquid capacity of around 1 quart, 38 ounces. Meanwhile, Harley-Davidson bikes released after 2006 take 45 fluid ounces for touring and Softail models. There are different types of oils used for Harley-Davidson bikes’ primary drive. The best oils that you can use are Mobil 1 Racing 10W 40 and 50 motorcycle oil.

A high-quality designed funnel will be required for pouring oil into the initial case. You must keep in mind that filling the Harley-Davidson primary Softail with 1 quart of primary liquid is often recommended.

You will have to be careful about how much oil your motorcycle holds, and follow the owner’s manual to find the details. If your Harley-Davidson bike was released after 2006, it will have oil capacities that vary from model to model. For instance, if you have a Softail, it uses 3 quarts of oil, you should start with 2 quarts. Then, you should gradually add more oil. After refueling, you need to go for a short ride and check your bike’s performance.

Why Primary Oil for Harley-Davidson Bikes is Suitable?

Amsoil 20W 50 Synthetic Motorcycle Oil is a suitable primary oil option not just for the primary but for the engine and transmission too. These parts of the motorcycles need to withstand constant friction and a lot of pressure. The role of primary oil will be immense if you want to prevent these hardships.

Many experts also recommend that you could use severe gear 75W 140 for your Harley’s primary. It is a type of gear oil that you can easily use as an alternative to 20W 50. You must keep in mind that you should use engine oil and gear oil in specific proportions.

Yes, the same engine oil can be used as primary oil. However, in Harley-Davidson bikes, it is recommended that you should use different oils for different purposes. It wouldn’t be a major issue if you use engine oil as primary oil.

How to Extract Primary Oil From Your Harley-Davidson Bike

Harley-Davidson isn’t a single-build motorcycle. Its engine comes assembled separately from the transmission and clutch. Since the transmission and engine are separate, a different type of oil will be used for each part. You will have to change the oil every 2,500 miles for maintaining high safety. But first, you need to warm up the engine when you change the oil.

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The reason why you need to heat the engine is so that you can bring it to the normal operating temperature. First, you have to do is place a drain pan under the initial Harley casing. After that, you should turn the drain plug using a 5/8 inch socket wrench and then open it such that all the oil gets accumulated inside gets put on top of the drain pan. After that, you should clean the drain plug and then put the Teflon tape on the plug before putting it back into place.

How to Know If the Primary Oil in Your Harley-Davidson Bike Has Gone Bad

Firstly, you should know that after every 2,500 miles, you will need to change the primary oil. Sometimes, the value of the oil condition remains the same, so how can you find know when it is the right time to change the oil. If you have a window on your Harley-Davidson bike’s primary case cover or oil dipstick, you need to check the color by inspecting the oil carefully. If the test indicates that the color of the oil is clear and brown, then you can come to the conclusion that the oil is still good.

In case it looks opaque and clack, you will have to change the oil quickly. When you rub bad oil between your fingers, you will notice a sort of firmness, whereas good oil will be relatively smooth. Another thing to keep in mind is that if the transmission of your Harley-Davidson bike is running louder than before, then it is high time that you change the oil.


How often do I need to change the primary oil of my Harley-Davidson bike?

How often you need to change the primary oil of your bike will depend on the model of the Harley that you are using. In the owner’s manual, you will be informed about the time of the primary oil change. Generally, you can drive about 2,500 to 3,000 miles after the previous change of the primary oil.

How full should a Harley-Davidson bike’s primary be?

The primary in a Harley-Davidson bike needs to be filled up to the bottom of the clutch spring. You should start with one quart and add little by little until the level reaches the bottom of the ring at the bottom of the clutch pack housing.

How much primary oil does a Harley-Davidson bike needs?

The amount isn’t that big. Primarily, most Harley-Davidson bikes need around 1 quart of primary oil. This might be a short amount of oil, but it will be important to run your bike smoothly.

Which oil should I be using as primary oil in my Harley?

Mobil 1 10W 40 is largely seen as a great option to use as a primary oil for Harley-Davidson bikes. However, you can also use 20W 50 oil as primary oil. You can even use synthetic oil as primary oil.

Can I use synthetic oil in my Harley-Davidson bike?

Yes, you can. Synthetic and conventional oil can be successfully substituted back and forth without having any compatibility issues or mechanical risks. This will hold true for the engine, transmission, and primary chain case.

Is Harley-Davidson’s engine oil and primary oil the same?

Harley-Davidson bikes require a special kind of oil known as primary oil, but it differs from engine oil. Primary oil will lubricate the moving parts inside the engine while also cooling it. On the other hand, the engine oil will lubricate the moving parts inside the transmission. Harley-Davidson recommends that you should use a different type of oil for different applications.

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