What Kind Of Oil Goes In Harley Primary: The Best Options To Go For


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What Kind Of Oil Goes In Harley Primary

Have you bought a new Harley-Davidson bike and want to take good care of it? If yes, then you’ll probably be interested in knowing what kind of oil goes in Harley primary. 

The type of oil that goes in Harley primary is the 20W-50 Synthetic Motorcycle Oil. There are a few decent alternatives that you can go for, but this one is recommended as the best option for your prized possession.

In this article, you will get to know all about what kind of oil goes in Harley primary, how you can change primary oil, and a lot more. Continue reading to know more.

What kind of oil goes into Harley primary?

For most Harley-Davidson models, the 20W-50 Synthetic V-Twin Motorcycle il is recommended for primary, engine, and transmission. It is essential to go for the right type of Harley-Davidson primary oil for your motorcycle. There are many great options that you can choose from, which is why sometimes it can be slightly tricky. However, there are some options that clearly come out on top as the superior options.

To protect your Harley-Davidson bike and keep it run smoothly, you must use the best primary oil available. Purchasing a Harley-Davidson bike is a fairly expensive investment. This is why it’ll need proper care and regular maintenance. This way, you will be able to ensure that it is running at its optimum best. Care and maintenance will also help the bike function optimally. Here are some of the best primary oil options that you can use for your Harley-Davidson motorcycle.

Mobil 1 Racing 4T 10W-40 oil

Easily one of the most highly recommended primary oil choices, Mobil 1 Racing 4T 10W-40 Oil is an amazing option. It is an exceptional choice for almost all Harley-Davidson motorcycle models. 

Mobil 1 Racing 4T 10W-40 oil is designed specifically to enable your Harley-Davidson bike to run with maximum efficiency. This will ensure that the engine in your Harley-Davidson bike is always clean. It will take the performance of your Harley-Davidson sport and cruiser bikes to a whole new level. If you love taking your bike for long drives, this option will be great for you. It’ll help you ensure that the primary and engine parts would be able to easily endure high temperatures.

Mobil 1 V-Twin 20W-50 oil

One of the best Harley-Davidson primary options to make your bike running smoothly is the Mobil 1 V-Twin 20W-50 oil. This oil option is specially designed for Harley-Davidson bikes with separate lubrication systems, and it’ll give an incredibly smooth performance. You can still use it on most Harley-Davidson bikes with a standard engine and transmission lubrication systems.

It even offers the correct frictional qualities needed for bikes with a moist-clutch engine and transmission systems to work seamlessly.

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AMSOIL Synthetic 20W-50

AMSOIL’s synthetic oils are popular when it comes to protecting the engine and primary oil options for Harley-Davidson bikes. AMSOIL Synthetic 20W-50, in particular, is one of the best-suited options as a primary oil option.

The AMSOIL Synthetic 20W-50 is a fully synthetic oil that can withstand heat efficiently. It’ll also reduce wear and tear in the metal parts of hot running bikes.

Benefits of 20W-50 primary oil for Harley-Davidson motorcycles

Some V-twin bikes in today’s market use a shared sump. This means they can use the same lubricant in the primary, engine, and transmission. Meanwhile, most Harley-Davidson bikes will use a separate sump for each lubricant. This presents Harley-Davidson riders with a choice. 

They can either use the same lubricant for all the bikes, or use separate lubricants labeled for each area. The 20W-50 synthetic V-twin motorcycle oil is highly versatile and can be used for all three – engine, transmission, and primary.

Harley Primary Oil

20W-50 oil comes with a number of benefits like –

  • Convenience – Harley-Davidson riders can buy and use one lubricant for multiple needs. This will reduce the cost while resulting in you won’t have half bottles of different lubricants lying around. It’ll be convenient to use the same oil for multiple needs.
  • Simplicity – Buying one lubricant that can fulfill the needs of multiple departments is simpler than buying three lubricants for three areas.
  • Great all-around performance – As this type of oil can work for all three areas of the bike, this makes it an exceptional all-around performer.

Multiple brands have formulated the 20W-50 synthetic motorcycle oil and turned it into an exceptional all-around lubricant. It will deliver amazing engine protection. Moreover, it has a proven ability to fight wear and tear, maintain cleanliness, reduce heat, and prevent corrosion during storage. 

Harley-Davidson heavy synthetic gear oil for primary

Harley-Davidson has formulated a high-quality primary oil for Harley-Davidson motorcycles. The brand knows the material needed for primary oil, which is what helps Harley-Davidson come up with the best type of oil for the best protection. The primary oil has been tested and certified for use as a high-quality primary oil and transmission in Harley-Davidson bikes. This heavy synthetic oil is specially designed for use in extreme environments like desert heat and cold weather. 

The Harley-Davidson SAE 80W-140 dual viscosity primary oil will be a great alternative for your bike. It comes with a pure synthetic base stock and proprietary additives, making it flow better even at a cold start. Further, the Harley-Davidson primary oil weight is simply the best. In high temperatures, the viscosity will act like a 140 weight oil that offers maximum protection and smooth performance. It will offer specialized lubricate for anti-wear requirements across a wider temperature range than mineral-based oil options. However, the problem with this one is that it isn’t always readily available and is quite expensive.

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How to add primary oil to your Harley-Davidson bike?

Once you know what kind of oil goes in Harley primary, now comes the time to add primary oil to the bike. Harley-Davidson bikes are fairly expensive. They’re very different from your common motorcycles in more aspects than one. For running efficiently, your Harley-Davidson bike will need the right tools and materials for protecting it from outside disruptive elements. Harley-Davidson motorcycles aren’t unit-constructed bikes. The engines and transmissions aren’t combined into a single assembly. Instead, the transmissions and engines of Harley-Davidson bikes are separately constructed and assembled.

This is why you’ll require oils that are designed for the engine and another one designed for the transmission. Your Harley-Davidson bike will also require primary oil for protecting the primary chaincase components. For safe operation, your Harley-Davidson bike will need to have primary oil replaced every 10,000 miles. When you’re changing primary oil, it is recommended that you must warm the engine first. After that, bring the engine to the normal operating temperature. It’ll make sure that the oil cooler thermostat opens up such that the previous oil drains out completely.

Prepare the tools

Changing the primary oil yourself will help you ensure that you can save more money. This is a pretty straightforward task that you can perform yourself if you know the right instructions. Before you start draining and adding primary oil, you must prepare a few tools.

  • Primary oil that has to be added
  • Funnel
  • New oil filter
  • Filter wrench
  • Oil drain pan
  • Socket kit
  • New O-ring
  • Primary case gasket 
  • Torque wrench
  • Hammer

Step-by-step instructions

1. Place your Harley-Davidson motorcycle on level ground

Put your Harley-Davidson motorcycle in a place that has level ground. The place needs to be properly ventilated so that you’re not troubled by the smell of oil. You must start the engine such that it becomes ready to operate as needed. This will help you drain out the used primary oil with ease and replace it with the new one.

2. Position the motorcycle for draining

Put your Harley-Davidson motorcycle in a position where you can begin to drain the old primary oil out. A vertical position would be the most ideal option. If your bike is on a kickstand, you should straighten it out and get it in an upstanding position. It will allow you to easily drain out the oil.

3. Remove the bike’s primary case cover

You should find the primary oil drain plug in the bike. You will find it right below the primary case. Furthermore, you should make use of a socket wrench for unscrewing the primary case cover. Typically, there will be five tools that you have to unscrew. Set the bolts and primary case cover aside.

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4. Remove the old, used primary case gasket

You will then have to remove the old gasket present on the primary case cover. Simply pull it out from its position. Now, clean the cover and put the new case gasket on the cover. It will easily drop right into place. Moreover, set the cover aside.

5. Remove the drain plug

Now, you’ll need to place the drain pan under the opened primary casing. Make use of a 5/8” socket wrench and then loosen the drain plug. Once you feel that it is easy to unscrew, simply remove the drain plug using your hand. Make sure that it doesn’t fall into the oil pan. Further, you should also clean the drain plug.

6. Drain the primary oil

Position the drain pan such that it can catch the draining oil perfectly. Now, drain out the oil completely from the primary casing.

7. Screw the drain plug again

Once the old, used primary oil has been completely drained out, you should screw the drain plug back into place. Before you do that, install the new O-ring on the drain plug. You can do this by simply using your hands. Then, make use of a socket wrench and a 5/8 socket for tightening the plug to its original place. If you’re making use of a torque wrench, simply set it to between 14 and 21-foot pounds and tighten the plug.

8. Refill the new primary oil

Once the drain plug has been tightly screwed on the drain hole, you can start to pour the new primary oil. You can visually check if the fluid you’ve added is at the right level. The primary oil must be touching the bottom of the clutch plate; otherwise, it is low in quantity.

9. Put the primary cover back again

Put the primary cover back and then tighten the five bolts manually with your hands. Then, you should use a torque wrench set at 14 to 21-foot pounds of torque for tightening the bolts. You can use the star pattern for tightening these bolts.


Thank you for reading. Hopefully, now you know all about what kind of oil goes in Harley primary, what are some of the best options, the alternatives, and more. Remember, it is important to maintain your bike, and this includes regularly checking the oil and changing it when required. This guide will help you change the primary oil and ensure that your bike continues running smoothly.

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