How To Check Primary Oil On Harley Davidson [Quick Ways]

Harley Davidson bikes use different liquid capacities and different types of oils for their primary drive. The 1980-2006 bikes have an initial liquid capacity of 1 quart and 38 oz, while the touring and Softail models released after 2006 use 45 oz.

The Harley Davidson bike’s oil holding capacity varies in different models. 

Primary oil is an essential lubricant that keeps the bike clean from various angles. Using fresh primary oil in bikes is necessary to get more mileage, reduce friction against bike parts, and expand the bike’s life.

Using quality primary oil, and changing and refilling it regularly enhances the engine’s life and improves the riding experience.

Checking and refilling the primary oil is an easy task and requires 30 minutes with simple steps in this guide to follow if you don’t know how to check primary oil on Harley Davidson.

How to Check Primary Oil on Harley Davidson?

To check primary oil remove the primary chain case. Inspect the fluid level from the bottom of the clutch basket. It should be 0.94 liters.

To change the primary oil follow the given steps.

Step 1:

Grab the necessary tools including

• a ⅝-inch socket
• A torque wrench
• A funnel
• A socket wrench
• Primary cover gasket
• New O-ring seal
• Lubricant or primary oil

Step 2:

Heat the engine for 15 minutes to process the oil to make it smoother and flow quicker. 

Step 3:

Find the drain plug and take a soft clean cloth to clean the engine drain plug and case. The drain plug resembles a screw and is present under the primary drain case. 

Once you find it, take a torque bit and socket wrench and loosen the bolts of the primary drain case to remove the cover.

Step 4:

Take a ⅝-inch socket and socket wrench to loosen the drain plug. Now place the oil pan below to drain all the oil from it.

Step 5:

Remove the primary case gasket Clean the drain plug, and install an O-ring seal off the drain plug properly. Fit the plug with a wrench.

Step 6:

Take a funnel and refill the primary oil. The funnel used to refill primary oil is different and is used to fill oil in the primary chain case. Once filled, put the cover back before tightening the bolts.

What is a Primary Oil in Harley Davidson Bikes?

A bike’s engine comprises several parts that work together to convert fuel into mechanical energy and efficiently run the bike. The process creates immense friction that can damage these parts of a bike’s overall performance and longevity.

The primary oil lubricates these parts, especially the primary chaincase. The primary chain takes power from the engine to the wheels.

This system must run smoothly, requiring primary oil to lubricate these parts. Therefore, regulating a proper regime to maintain the primary chain case and changing the primary oil is necessary for Harley Davidson bikes.

Harley Davidson motorcycles can use the same oil to lubricate the engine, transmission, and primary chain case.

This oil helps to cool the engine by carrying heat away from critical elements. Over time, this oil due to excessive breakdown becomes ineffective and requires the rider to change it.

How Much Primary Oil Goes in Harley Davidson?

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 and amount of the primary oil.

Always fill the primary oil up to the bottom of the clutch spring. Start with one quart and then add little by little until it reaches the shiny ring at the bottom of the clutch housing. 

Avoid adding too much primary oil to the bike as it will increase the pressure on the crankcase. This results in forcing out the oil from the components into the intake system, damaging the engine.

Recommended Primary Oils for Harley Davidson

Before selecting primary oil, consider the optimal additives and viscosity of oil in comparison with the viscosity level.

1. Amsoil 20W 50: Synthetic Motorcycle oil to combat friction and pressure.
2. Severe Gear 75W 140: Gear oil to use as an alternative to Amsoil 20W 50.
3. Mobil 1 Racing 4T 10W 40 Protects in extreme operating conditions.
4. Red-Line 42904: V-twin Synthetic Oil to improve clutch operation and resist corrosion.
5. Lucas 10790: Primary Chaincase oil.
6. Red Wing Heritage Mink oil

How Often Primary Oil Should be Changed?

Change primary oil every 2500 to 3000 miles. Harley-Davidson bikes change it after every 5,000 miles of riding. You can stretch it to 10,000 miles. Change semi-synthetic oil after 5,000-6,000 miles. Change fully synthetic oil after 7,000-8,000 miles.

Symptoms of Low Primary Oil

Oil condition sometimes remains the same making it difficult to know when to change the oil. Inspect the oil carefully through the oil dipstick or the primary case cover and check for color changes. If the oil is clear and brown, it is in good condition.

Other signs indicating to change primary oil are:

• Motor Running Hotter

Harley Davidson bikes have temperature gauges to tell that the bike is overheating but in 2021 models, there are digital meters to read the engine’s temperature. The bike overheats to an extent that makes it difficult to use it on low oil. 

• Metal Burning Smell

When the oil in the bike is not thick enough to lubricate the metal parts begin grinding each other causing heat that releases metal-burning smell.

Change primary oil with a heavy-weight oil to provide extra lubrication for the engine. Adding a viscosity modifier to oil also thickens it up and makes it serve for longer.

• Metal Clanking Sound

The bike’s engine makes a clunking sound caused by loose rods, bearing failure, metal shavings, and early signs of low oil in Harley.

Clean and well-leveled oil provides a layer of protection between the high-revving metal engine components. When this level is low, the engine loses that layer of protective coating and creates a racket of metallic clanking sound.

• Fails to Run

Low primary oil in Harley leads to difficulty starting and uneven idling. Insufficient primary oil also causes trouble firing up and requires you to check the oil level immediately.

• Dry Primary Chain

Check the Harley’s primary chain. A dry primary chain causes the breaking of chains and damage to the bike’s engine. If it is dry, clean it, and add fresh primary oil to lubricate. 

• CEL Stays On

The Check Engine Light stays on. It is a definite warning sign of a low oil level, indicating a serious problem like blockage or a damaged gasket or seal.

• Unsmooth Clutch Operation

The oil keeps the clutch pack lubricated and when low on primary oil the rider notices unsmooth clutch engagement associated with difficulty in shifting gears. Lack of primary oil leads to clutch pack failure and requires replacement due to friction.