6 Common Harley 114 Engine Problems and Solutions [EXPLAINED]

The most common Harley 114 engine problems include cold starting, oil aeration, gear or clutch problem, wet sumping, etc. If not solved immediately, these problems can eventually lead to severe engine damage.

For example, continuing wet sumping can lead to power loss, or a faulty clutch can make your bike literally useless. So, there’s no other option than identifying and fixing these problems immediately.

But first, you must know the reason behind the issue before taking any action. So, let’s explore possible problems and ways to fix them.

Troubleshooting and Fix for Harley 114 engine problems 

Even after so many updates, the Milwaukee Eight, commonly known as the M8 engine, has several issues, according to Harley 114 owners. Let’s discuss some of the most common problems and how to fix them.

1- Wet sump issue

This is maybe the most common complaint from HD 114 riders. A wet sump indicates a sump or sink for the lubrication oil. 

After completing lubrication, oil deposits in the crankcase. This may cause an imbalance in engine parts.

If you notice that the engine is not generating enough power or getting overheated, this may be a wet sump problem. 

To make sure, check the crankcase and gearbox to see whether there is an oil deposit or not.

If there’s too much and needs to be cleaned, do it immediately. Monitor the oil supply line regularly. 

However, removing the spark plug and then cranking the engine may recirculate some used oil.

Depending on the severity, the cost of fixing can vary. If you have proper tools, you can clean the sump yourself without spending anything.

Read Also: Harley 6 Speed Transmission Problems: Diagnose And Easy Fixes

2- Aeration of oil

Due to wet sumping and oil pumping issues, sometimes outside air dissolves in the oil. This phenomenon is called “aeration”. 

Because of aeration, the oil loses its effectiveness, and the engine fails to generate targeted power. It also increases the stress on internal parts, which may eventually lead to breakdown. 

Noise from the gearbox, lack of power generation, etc. are the symptoms of oil aeration. In this case, you may need to change the head gasket to prevent this.

Switching to S&S lifters can be a solution too. A head gasket for the HD 114 engine can cost you about $50-$60. 

3- Cold starting problem

When the bike is kept idle for a long time, the engine becomes lousy. The power of the battery also decreases due to inactivity. 

That’s why, when starting the engine after a long period, it may take time to warm up and cause slow starting issues.

Sometimes, you may notice there is an adequate amount of fuel, the spark plug is on, still the combustion is not taking place. This indicates the cold starting problem.

Though in most cases, it’ll work after some attempts at starting, if the battery goes down, you may need to recharge or even replace it. 

Well, cleaning the spark plug can also be a solution in some cases. However, replacing the battery of the Harley 114 engine can cost $70.

Read Also: Harley Davidson 103 Compensator Problems: Causes And Solutions 

4 Gear transmission Issue

Some owners of this bike claimed that after starting the engine, the gears didn’t engage. No matter which gear they are in, the bike doesn’t move even after releasing the clutch.

This happens when the clutch plate is not working or the clutch fluid is leaking. The wear of gear can also cause this issue. But it’s rare for a piece of gear to wear so much unless it breaks.

Replacing a clutch plate or fixing gears can be a solution to this. Anyway, it’s a problem that can only be solved by professional technicians.

The cost can vary depending on the damage or severity of the problem. 

5- Faulty clutch

This is similar to the previous problem, except this one is basically factory based. The clutch on many Harley 114 bikes does not work properly. 

As a result, after starting the engine and shifting gears, the bike doesn’t move.

While driving, if you notice an anomaly in gear shifting or braking, this may be a symptom of a faulty clutch.

This can be fixed only by factory-level facilities. That’s why Harley has recalled about 200,000 bikes to solve this clutch problem. 

If you have a warranty on the product, you can enjoy free service since it’s a factory-made issue.

Read Also: 5 Common Harley Davidson Evolution Engine Problems & Solutions

6- Detonation and deposits

Due to driving for too long, sometimes carbon particles deposit on the engine head. This led to the detonation of the engine.

You’ll hear continuous metallic sounds, and if you look inside the engine head, there’ll be damage due to carbon deposits.

Regularly cleaning the engine and using high-quality fuel can solve this problem. And of course, this won’t cost you any additional money since it’s mandatory to regularly check and maintain the bike.

Tips To Prevent Harley 114 engine issues

For any engine, frequent checkups and repairs are the key to optimum performance. To prevent problems with the Harley 114 engine, you can follow these tips.

  • If you notice any miss calculation in acceleration reading, immediately check your bike since it can be a symptom of crankshaft failure.
  • Excessive engine vibration is another issue to be concerned about. Whenever you see this, check the gearbox, crankpin, and piston.
  • Always use high-quality oil to ensure long-lasting engine performance.
  • You can use low-viscosity oil to ignore the oil aeration problem.

Read Also: Harley Davidson 1200 Sportster Common Problems

Should You Buy Used Harley Motorcycles with 114 Engines?

If the engine was made after 2009, then it’s okay to buy one. Otherwise, you may need to give it a second thought. Why? Let’s explain. 

  • Though Harley M8 114 engines are iconic and well-performing, those which are made before 2009 have very poor market value nowadays.
  • The previous versions have several issues like oil leakage, loose piston, etc. In later models, Harley overcame these. So, buying the later versions will be wiser.
  • The Harley 114 engine is the best among all of its predecessors, even some later models. It has a greater compression ratio than the 88 and 107 models.
  • The older versions’ parts are not widely available. So if you buy a newer version, it’ll be easier to fix. 


Worldwide, fans of Harley Davidson are always asking different questions about 107, 114, or 117 Harley engines. Among those, let’s see some of the most popular queries and their answers.

Is Harley 107 Or 114 Better?

The 114 is an upgraded version of the 107. 114 comes with some improvements in terms of performance. The 114 is capable of producing 10 horsepower and has a greater compression ratio. Most of the other things are quite similar. 

What Is The Difference Between Harley 114 And 117?

The 117-engine Harley can produce 24% more power than the 114 engines. The increased engine size and capabilities add about 5% more torque than the 114. The suspension of the bikes with the 117 version is also better.

How Long Are Harley Engines Good For?

A Harley engine can serve perfectly for 40000 to 50000 miles, depending on the maintenance quality of the engine. Using higher-grade oil and quality parts can increase it even more.

Final Words

Undoubtedly, Harley Davidson has produced some of the best engines of all time, and the Harley 114 is one of them. But like many of their other products, this engine also contains some drawbacks.

Issues like cold starting, or engine heating may be solved quickly. But oil aeration or wet sumping may have a long time effect on the engine.

So, taking immediate action to fix these and maintain the bike regularly is the foremost task for every Harley rider.

Read Also: Harley 131 Problems: What You Need To Know!

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