Do Harley Davidson Motorcycles Leak Oil? (Solved & Explained)

Harleys are unreliable. Harleys are overweight and overpriced. Harleys are oil-leaking pieces of junk.

These are some of the most prevalent criticisms of Harley-Davidson motorcycles. However, the most enduring of these is that Harleys leak oil. Is it true that Harleys leak oil?

Let’s find out!

Do Harleys Leak Oil?

Harleys do not leak engine oil. Early Harleys used an automatic lubrication system that drew oil from the oil pump to lubricate the primary chain. What seems like oil leaking from the motorcycle is actually excess oil dripping off from the primary chaincase.

The oil would drop off from the primary chain into the primary chaincase, which had a drain hole that allowed oil to drop to the floor.

The resulting puddles on the floor lead people to believe that Harleys leak oil.

Do Harley-Davidson Motorcycles Typically Leak Oil?

As we said earlier, Harley critics describe that oil leaks are not oil leaks in the truest sense.

Do Harleys leave oil puddles on the floor when parked? Yes.

However, these oil puddles are not the result of a systemic defect in the motorcycle design. Rather, they are a by-product of Harley’s automatic lubrication system.

Let’s explain.

Oil & Lubrication Distinction

Early Harley Big-Twin engines had a separate engine and transmission connected via a primary drive chain.

This chain transferred power from the engine to the transmission. As this chain was prone to overheating, Harley engineers had to devise a way to keep the chain constantly lubricated.

The engineers ran a tube from the oil pump into the back half of the chain cover. This way, oil from the oil pump would drip over the primary drive chain to lubricate it.

The oil that dripped off the chain would collect in the primary chaincase and finally onto the ground; the chaincase had a drain hole. Therefore, the oil puddles are merely the result of Harley’s automatic chain oiling system.

Many Harley critics do not know of the automatic lubrication system. Hence, you’ll hear a lot of jokes about “those big, old, leaky Harleys.” Don’t be surprised. The idea that Harleys are big, noisy, oil-leaking bikes is old, and many now take it as the gospel truth.

Harley-Davidson stopped using automatic chain oilers in 1964, and all lubrication had to be done by hand.

Although this reduced the oil leaks, it did not solve the problem.

Do New HarleyDavidsons Leak Oil?

For long, the motorcycle-buying public did not care if Harleys leaked oil or not.

Showrooms would place cardboards under Harleys on display to prevent the oil puddles from staining the floor. Oil leaks were as part of the Harley image as the unique engine note.

However, as the newer Japanese models became popular, those oil leaks led to a decline in Harley bikes’ sales. Japanese motorcycles such as Honda had oil-tight engines that never left oil puddles as Harleys did.

This forced Harley-Davidson engineers to make some changes to the motorcycle design to eliminate the leaking oil issue.

The first such change was to seal the primary chaincase so it did not leak oil like before. The rear-drive chains also disappeared, removing the need for a rear chain oiler.

A new wet clutch, which did not drip oil, was introduced. This cooled the stator (which had been relocated to the primary). Still, with all these changes, you may find small leaks on Harley motorcycles today. The biggest difference is the leaking is less severe compared to the past.

One of the common leaks on Harleys is the wet-sump. Most Harleys are dry-sump bikes, and a separate oil tank holds the oil and pumps it into the system when needed. This oil tank is located above the oil pump.

A check valve holds the oil in the tank when the bike is not in use.

The problem is the check valve may eventually wear out and allow the oil to escape from the oil tank. Dirt and grit, weak spring pressure, etc., can also cause the check valve to allow the oil to slip.

When you start the motorcycle, it pumps the oil out of the engine. Thus, the oil finds its way onto the floor, and you notice puddles beneath your Harley.

The bike engine “breathing” into the air cleaner causes another common leak on Harley motorcycles. Unlike other brands, the air cleaners on Harleys are visible and hang by the motorcycle side.

Motorcycle engines typically “breathe” an oily gas mixture into the air cleaner housing. With time, the oily gas keeps collecting and turns into oil in the air cleaner housing. Once the air cleaner housing is full, the oil will start leaking out and cause puddles on the floor.

The above issues aside, Harleys have become extremely oil-tight and do not leak lube.

You should also be reading our article which talks about Do Harley-Davidson Boots and Clothes Run Big

Are These Issues Covered By The Warranty?

All problems on your Harley motorcycle, while it is still under warranty, should normally be repaired free.

That includes oil leaks and other fluid discharges too.

However, there may be certain clauses involved that may prevent you from getting your oil leak fixed under warranty. For example, if an aftermarket modification is responsible for the leaks, the dealership may decline to fix the issue under warranty.

Besides, warranty coverage plans also vary in wording. Some warranties may cover the cost of replacing the leaking part but will not cover the labor costs.

Other warranties may cover the payment for replacing the faulty component but do not cover damage caused by the leaking oil.

The best you can do is ask your dealer if your motorcycle warranty covers oil leaks.

If the motorcycle is a pre-owned one and you plan to buy an extended warranty, check if the extended warranty plan covers future oil leaks.

How To Make Sure Your Harley Davidson Doesn’t Leak oil:

Here are some measures you can take to prevent oil leaks on your Harley motorcycle:

1. Ride Your Motorcycle Regularly

This may seem simple, but in reality, it goes a long way in preventing motorcycle oil leaks.

As we mentioned before, long periods of non-use cause your gaskets to wear out faster and leak oil.

For a better illustration, think of the gasket as a rubber band. If you don’t use it, it becomes brittle and breaks easily. However, the more you use it, the longer-lasting it becomes.

This applies to gaskets. Unused gaskets will develop body defects, which will inevitably cause leaks.

2. Prompt and Regular Oil Changes

Did you know that old oil in your motorcycle’s engine could corrode the engine?

Leaving old oil in your engine could damage the engine gaskets, too.

Old oil has acidic elements, which can eat away at the gaskets and cause them to develop holes.

You may say, “I was told engine oil has additives that prevent the oil from becoming acidic over time.”

Yes, engine oil contains additives designed to stem the build-up of any form of acidity.

However, these additives dissipate with time, and acid elements form in the oil.

3. Routine Inspection

The key to preventing major leaks on your Harley is discovering the small leaks before they become problematic.

A good way to do this is to inspect your motorcycle after a long, hard ride.

Do a check of all parts of the motorcycle and see any oil spots or signs of a potential oil leak. Be thorough.

Sometimes oil leaks pool up in an obscure area and drain off once the bike has cooled, and you may not discover them until the oil leak becomes big.

Where Does The Oil Leak From On A Harley Davidson?

Despite its well-engineered design, your Harley is still a motorcycle.

And every motorcycle can leak oil, especially if certain components are faulty.

Apart from the leaks from the air cleaner and primary chaincase, there are other places where oil can leak from on Harley motorcycles.

1. Gaskets

Although many people do not know, faulty engine gaskets are a common cause for oil leaks on motorcycles.

Because they are constantly exposed to high internal pressure, gaskets are prone to wear.

When a gasket wears, cracks, holes, and other weak spots develop. In time, the pressure will push out the oil via these holes, causing a leak.

Leaving your Harley in the garage for long periods could cause the gaskets to wear out faster than normal. While this may seem counterintuitive, it is the truth.

Riding your Harley regularly allows the gaskets to heat and expand. This way, the gaskets are exercised and wear out less quickly.

Leaving your bike parked in the garage means the gaskets do not see adequate usage. Lack of usage will cause gaskets to become brittle and wear out quickly. Brittle gaskets are prone to cracks, which could lead to oil leaks.

The most common gaskets prone to leaking oil on your motorcycle are the valve cover gasket, crankcase gasket, oil pan gasket, and cylinder head gasket. These gaskets are typically exposed to extreme internal pressure, and oil can leak out of the weak spots.

2. Oil Plugs

Bad oil plugs are another culprit responsible for oil leaks on motorcycles, such as Harleys.

Side crankcase plugs and valve cover plugs can also be a source of leaks on your Harley motorcycle.

Oil drain plugs leak when they are not tight. Vibrations on the motorcycle can cause the oil drain plug to come loose, leading to oil leaks.

Also, the O-rings on the oil drain plugs can wear out, become brittle, and ineffective. Once this happens, the oil will leak.

How Do You Clean Up Oil Spill On The Ground?

Is your Harley leaking oil, and you want to get rid of the puddles on your garage floor?

Here is a step-by-step explanation detailing how you can eliminate oil spills:

1. Soak the Oil Stain:

Usually, the first thing to do when trying to clean up an oil spill is to soak up as much oil as you can.

To do this, sprinkle sawdust, coconut husks, or an oil-absorbing agent on the stain. You can also try clay kitty litter [ensure it is not the kind that clumps].

Leave the absorbing agents on the oil spill for 24 hours to 48 hours and sweep the debris with a broom and dustpan.

2. Saturate the Oil Stain:

Sometimes, the oil stain can be stubborn that soaking it up may not eliminate it.

If this happens, here are a few things you can try:

  • Laundry detergent
  • Water mixed with liquid dishwashing soap

Applying any of these to the oil spill will break up the stain and prevent it from solidifying.

3. Start Scrubbing:

Once you apply a cleaning agent to the oil spill spot, scrub the area.

It would be best to do this with a quality wire brush to penetrate the concrete and remove stains easily.

You can reapply any of the cleaning solutions you used in the first or second steps as you are scrubbing too.

Douse the area with water when you finish scrubbing and allow it to dry.

How Do I Know Where Oil Is Leaking From On My Harley?

Detecting the source of an oil leak on your Harley motorcycle can be difficult.

Because multiple places can leak, it is near impossible to know which area is leaking oil at first glance.

Mechanics use many high-tech tools to detect the exact location of oil leaks. However, the chances are that you do not have these tools.

Here is a quick guide you can use to detect oil leaks:

  1. Try placing a piece of cardboard directly beneath the motorcycle and note the location of the oil drips.
  2. This should give you an idea of where the oil is coming from.
  3. Use the paper towel method.
  4. Wrap paper towels tightly around the engine and use tape to hold the paper towels in place.
  5. With time, the exact location of the leak will manifest.
  6. Be careful to do this only when the engine is cool.
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