Harley Davidson Primary Oil Substitute [Top 3 Picks]

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It is important to select the right Harley Davidson primary oil for your bike. There are many primary oils to choose from, so it can be difficult to choose the best one. What is the best Harley Davidson primary oil substitute?

The best Harley Davidson primary oil substitutes are as follows:

  1. Red Line (42904 V-Twin Primary Case Oil – Click here to see it on Amazon – our #1 top pick!
  2. Spectro R.HDPCO Premium Primary Chaincase Heavy Duty
  3. Red Line 42504 20W50 Motorcycle Oil Synthetic

Read on to learn more about the function of primary drive oils in Harley Davidson motorbikes, their importance, the different brands of primary oils for Harleys, and how to change the oil.

Also, take a look at our top Harley Davidson primary oil substitute on Amazon, the Mobil 1 Racing 4T 10 W-40 Oil, to see its price and great reviews:

Click here to see it on Amazon.

Best Harley Davidson Primary Oil Substitute

To protect the primary drive, you need to use the best primary oil that is available. Your Harley is an expensive bike that provides high-quality drive to you and your passenger. To ensure that it will always run at its optimum, you need to give it the best tools to will enable it to function optimally.

Here are some of the best primary oils that you can use to ensure that the primary drive of your Harley will be working at its best.

1. Red Line (42904 V-Twin Primary Case Oil

Click here to see it on Amazon.

Red Line 42904 V-Twin Primary Case Oil serves as a premium substitute for Harley Davidson Primary Oil, catering to the needs of V-Twin American motorcycle engines manufactured from 1984 to the present.

This includes Evolution, Twin Cam, and aftermarket engines designed similarly. Renowned for its high-quality formulation, Red Line’s V-Twin Primary Case Oil is a testament to the brand’s commitment to producing top-tier products.

One of the standout benefits of this primary case oil is its capacity to enhance vehicle performance. Specifically designed for wet-diaphragm spring clutches in the primary chaincase, it significantly improves clutch operation while concurrently reducing wear and temperature.

This results in a longer lifespan for the clutch, contributing to sustained and efficient performance over time. Whether on motorcycles, ATVs, or other powersports vehicles, Red Line’s primary case oil ensures optimal functionality across a range of applications.

What sets Red Line apart is its long-standing reputation for excellence since its establishment in 1979. The brand has consistently delivered products that outperform and provide superior protection compared to others on the market.

Red Line makes no compromises when it comes to quality, and their V-Twin Primary Case Oil is no exception.

A crucial aspect of this product is its formulation as a friction-balanced case oil. Unlike many synthetic oils that can be excessively slippery for clutch operation, Red Line has carefully crafted a balanced oil.

This unique formulation limits slip while ensuring a smoother operation of the clutch.

This thoughtful design addresses a common concern in the realm of lubricants for V-Twin motorcycles, making Red Line’s V-Twin Primary Case Oil a reliable and performance-focused choice for riders who demand the best for their machines.

2. Spectro R.HDPCO Premium Primary Chaincase Heavy Duty

Click here to see it on Amazon.

The Spectro R.HDPCO Premium Primary Chaincase Heavy Duty is a specially formulated oil designed to serve as a high-quality substitute for Harley Davidson Primary Oil.

Manufactured by Spectro, a reputable brand known for its commitment to producing premium lubricants, this particular product is designed to meet the demanding requirements of Harley Davidson motorcycles, providing reliable performance and protection for the primary chaincase.

The key specifications of the Spectro R.HDPCO include a weight of 1.78 pounds and product dimensions of 14.5 x 14.5 x 27.3 inches.

The exterior is painted, adding to its durability and visual appeal. As indicated by the model number R.HDPCO, this oil is specifically formulated for heavy-duty applications in the primary chaincase of Harley Davidson motorcycles.

One notable aspect is that the Spectro R.HDPCO Premium Primary Chaincase Heavy Duty has not been discontinued, ensuring continued availability for Harley Davidson enthusiasts who rely on this oil for their maintenance needs.

The manufacturer part number R.HDPCO uniquely identifies this product, making it easy for users to locate the correct oil for their Harley Davidson motorcycles.

While the provided information outlines the essential details and specifications of the Spectro R.HDPCO, specific performance characteristics, benefits, and application details may be available through the manufacturer’s documentation or product literature.

As with any lubricant, it’s essential to follow the manufacturer’s recommendations and guidelines for optimal use in Harley Davidson primary chaincases, ensuring peak performance and longevity for the motorcycle’s critical components.

3. Red Line 42504 20W50 Motorcycle Oil Synthetic

Click here to see it on Amazon.

The Red Line 42504 20W50 Motorcycle Oil Synthetic serves as an excellent substitute for Harley Davidson Primary Oil, especially in the latest Big-Twin motorcycle engines that require 20W50 motor oil.

This includes engines such as Milwaukee-Eight, Evolution, Twin Cam, and other aftermarket engines with similar designs.

Red Line’s commitment to quality and innovation is evident in the careful formulation of this synthetic motorcycle oil, catering to the specific needs of high-performance Harley Davidson engines.

One of the standout features of the Red Line 42504 is its superior film strength, achieved through the use of ester base stocks. Ester base stocks provide enhanced protection and contribute to improved ring seal, ensuring optimal engine performance.

This synthetic oil is engineered to withstand the demanding conditions of motorcycle engines, providing reliable lubrication and protection under high-stress situations.

Extended drain intervals set the Red Line 42504 apart from other brands, thanks to its utilization of higher quality base stocks and excellent dispersants.

This not only reduces the frequency of oil changes but also contributes to cost savings and environmental sustainability. Riders can have confidence in the longevity and durability of their engines with the extended protection offered by this synthetic motorcycle oil.

Red Line has carefully blended this oil with specific friction modifiers that are compatible with wet clutches, ensuring smooth operation and longevity of these critical components.

The compatibility with wet clutches is crucial for motorcycles, especially those with high-performance engines, where the oil must provide effective lubrication without compromising the functionality of the clutch.

Furthermore, the Red Line 42504 meets the requirements for JASO MA/MA2 applications, signifying its suitability for a wide range of motorcycles, including those with wet clutches.

This certification ensures that the oil meets the industry standards for motorcycle oils, providing riders with confidence in its performance and compatibility with their Harley Davidson motorcycles.

Harley Davidson Heavy Synthetic Gear Oil

There is primary oil that Harley Davidson formulated. They know the material they used for the primary drive. Thus, they know the best type of oil that will provide the best protection. It is tested and certified for use in the primary chain cases and transmissions of Harley motorbikes.

This is heavy synthetic oil designed for use in extreme temperature environments, such as cold weather and desert heat, heavy load riding applications, and frequent two-up riding conditions.

The oil grade is SAE 80W-140 dual viscosity heavyweight and primary oil. It has proprietary additives and pure synthetic base stock that makes it flow better at a cold start-up. Its Harley Davidson primary oil weight is the best. In high temperatures, its viscosity acts like a 140 weight oil which can provide maximum protection.

The problem is that this oil can be hard to find and expensive. So instead, you can choose any of the substitutes listed above.

How to Change the Primary Oil in Harley Davidson Motorcycles

harley davidson primary oil substitute

Harley Davidson motorbikes are quite expensive. They are different from the common motorcycle in many respects. To run efficiently, it requires the tools and materials that will best protect it from outside disruptive elements.

Harleys are not unit-constructed bikes. Their engines and transmissions are not combined into one single assembly. The engines and transmissions of Harleys are separately constructed and assembled. Their engines are separately assembled from the transmission and the clutch.

That is why they need lubricating oils designed for the engine and another for the transmission. Each separate system has to be fed with its own oil type. And for safe operations, you should replace them every 2,500 miles.

When changing the primary oil, it is recommended for you to warm the engine first. You need to bring the engine to its normal operating temperature. It will ensure that the oil cooler thermostat will open up so that the previous oil will drain out properly.

Prepare the Following

Changing the primary oil yourself will enable you to save money. This is a fairly straightforward task that you are perfectly able to perform. But before going on to drain and change the primary oil, you need to prepare the following things.

  • New motorcycle primary oil
  • New oil filter
  • Funnel
  • Oil drain pan
  • Filter wrench
  • Socket kit
  • New primary case gasket
  • New O-ring
  • Hammer
  • Torque wrench

1. Place Your Bike on Level Ground

Put your bike in a place where there is level ground. The place should also be well ventilated, not to be bothered by the smell of the lubricating oil. Start the engine so that it will operate as it used to. This will help drain out the old primary oil easily.

2. Position the Bike for Draining

Put the bike into a position where you can start draining the old oil out. A vertical position will be the most ideal. If the bike is on a kickstand, straighten it out to assume an upstanding position. This will enable the old oil to drain out easily.

3. Remove the Primary Case Cover

Find the primary oil drain plug. It should be right below the primary case. Use a socket wrench to unscrew the primary case cover. Typically, there are five bolts that you need to unscrew. Set these bolts and the primary cover aside.

4. Remove the Old Primary Case Gasket

Remove the old gasket on the primary case cover. Just pull it out from its place. Clean the cover and then put the new gasket on the cover. It should easily drop into place. Set the cover aside.

5. Remove the Drain Plug

Place the drain pan directly under the opened primary casing. Use a 5/8 inch socket wrench and loosen the drain plug. Once you feel it is easy to unscrew, remove the drain plug with your hand. See to it that it doesn’t fall into the oil pan. Clean the drain plug.

6. Drain the Old Primary Oil

Position the drain pan so that it can directly catch the draining oil. Drain out all the oil completely from the primary casing.

7. Screw Back the Drain Plug

Once the old primary oil is completely drained out, you need to screw that drain plug back in its place. But before doing that, install the new O-ring on the drain plug. Use your hands to do it. Then use a socket wrench and a 5/8 inch socket to tighten the plug to its original place. If you are using a torque wrench, set it to 14 to 21-foot pounds to tighten the plug.

8. Refill the Primary Case with New Oil

Once the drain plug is tightly screwed on the drain hole, start pouring in the new primary oil in the required amount. Visually check if the fluid is at the right level. The primary oil should be touching the bottom of the clutch plate.

9. Put Back the Primary Cover

Place the primary cover back on its position and then hand-tighten its five bolts. Then use a torque wrench set at 14 to 21-foot pounds of torque to tighten the bolts. Use the star pattern in tightening these bolts.

When to Change Your Harley Davidson Oil?

harley davidson primary oil weight

Generally, all bike manufacturers recommend changing the oil every 5,000 miles. Harley says it should just be after every 2,500 miles. Other than that, other signs will tell you if your motorcycle needs a primary oil change:

1. The Primary Oil Looks Black

If your primary case cover has a window or your motorcycle has an oil dipstick, check the oil color. Good oil still has a translucent brownish color. But if it is already black and opaque, you need to change it at once.

2. It Feels Gritty

A good oil will feel smooth on your fingers. But if you notice some grittiness on it, you need to change it promptly.

3. Transmission Runs Louder Than Before

If you notice that the transmission is running louder than before, the oil must have already gone bad. A transmission system will sound good if the oil is still good. But if the sound deteriorates, one of the culprits is bad lubricating oil.

About Harley Davidson Primary Oils

A Harley Davidson motorcycle is a beautiful piece of machinery that you should maintain very well if you want to take advantage of what it has to offer. One of the chores that you should not miss is changing its primary oil.

Mobil 1 Racing 4T 10W-40 Oil

One of the best primary oils that you can use for Harley Davidson bikes is the Mobil 1 Racing 4T 10W-40 oil. You can also choose to use the Mobil 1 V-Twin 20W-50 oil. Either one of these two oils will do a great job of lubricating the primary drive of your Harley.

Click here to see it on Amazon

AMSOIL Synthetic 20W-50 Primary Oil

For Harley twin-cams, the AMSOIL Synthetic 20W-50 primary oil goes highly recommended. You can use them in all three holes in your motorbike. Amsoil has now produced a dedicated fluid you can use in Harley motorbikes’ transmission and primary cases.

Why do you need to use primary oil in your motorcycle? The primary gets very hot when the motorcycle is running. As you know, metal expands when subjected to high temperatures. The primary oil, aside from helping to reduce friction, also helps to cool down the temperature of the primary drive components.

If you don’t use the right primary oil in your Harley, you will eventually experience problems with your primary drive. The recommendation is to use the best primary oil and to change this oil every 5,000 miles.

Why the Primary Drive of a Harley Davidson Needs Lubrication

The primary drive of your Harley is composed of a pulley or engine output sprocket, which is attached to the crankshaft of the engine. Also included in the primary drive parts are the roller chain belt, the clutch assembly, and the housing or casing that holds the whole assembly. The clutch engages the primary drive to the transmission.

All these primary drive components move in sync when the motorbike is running. And when a Harley is running, heat is generated by the metal parts inside its engine and drive components because of the speed by which they are running.

Typically, the temperature of the primary drive at the rear and over the clutch when the motorbike is running is measured at around 98°F. At the front, where the engine block and crankcase are located, the temperature is measured at about 103°F.

Meanwhile, the measured temperature at the inner primary drive (where the compensating sprocket is located) is around 174°F.  As you well know, metal parts that are subjected to heat expand. You need to lubricate these parts with oil so that there will be a friction reduction between them. The oil will also help to control or cool down the heat generated by these metal parts.

The primary gets so hot when you drive your Harley. As you know, metal expands when they are subjected to high heat. The primary oil, aside from being a friction aid, also helps to cool down the temperature of the primary drive.

Conclusion: Harley Davidson Primary Oil

If you own a Harley Davidson motorcycle, there are several primary drive oils that you can use. One of your best choices is the Mobil 1 Racing 4T 10W-40 motorbike oil. You can also choose to use the Mobil 1 V-Twin 20W-50 primary oil.

Harley Davidson also makes its own primary oil. It is specifically designed to protect and prolong the life of their primary drives.

Again, here are the steps you can follow to change your Harley Davidson Motorcycles’ primary oil:

  1. Place Your Bike on Level Ground
  2. Position the Bike for Draining
  3. Remove the Primary Case Cover
  4. Remove the Old Primary Case Gasket
  5. Remove the Drain Plug
  6. Drain the Old Primary Oil
  7. Screw Back the Drain Plug
  8. Refill the Primary Case with New Oil
  9. Put Back the Primary Cover