Most Reliable Harley Engine (Find Out Which of Harley Engines is the Most Reliable!)

Last Updated on January 9, 2023 by Leepu Da Maxim

Some of the most reliable Harley-Davidson engines are the Screamin’ Eagle 131 Softail engine, the Evolution engine, the Twin Cam 88 engine, the Twin Cam 96 engine, the Milwaukee-Eight engine, etc.

Key Takeaways

  • The Screamin’ Eagle 131 Softail engine is a V-twin engine with a displacement of 131 cubic inches and it can produce over 100 horsepower and 120 foot-pounds of torque
  • The Evolution engine is a gasoline-powered internal combustion engine and it is well known for high power output, reliability, and durability
  • The Twin Cam 88 engine is a V-twin engine and it was used in a wide variety of Harley-Davidson models until 2006
  • The Twin Cam 96 is a V-twin motorcycle engine with a displacement of 96 cubic inches (1584 cc)
  • The Milwaukee-Eight engine is an eight-valve, air-cooled, V-twin motorcycle engine that was introduced by Harley-Davidson as a replacement for the Twin Cam engine

Key Features Of The Most Reliable Harley Engine

More PowerRiders with this engine notice a greater amount of horsepower, as well as superior torque power.
Replacement PartThis is an engine that should be purchased as an upgrade for some motorcycles. 
CompatibilitySome touring motorcycles, such as Harley Davidson 2017 and later, may incorporate this engine.
Higher PerformanceIn general, the highest performance can be noticed at high speed. In turn, the engine has a longer life.
Relationship Between Mechanics And TechnologyThis engine offers excellent quality standards thanks to the balanced amount of mechanics and technology incorporated.

What Is The Most Reliable Harley Engine? 

Almost every Harley Davidson fan agrees that the Screamin’ Eagle 131 Softail Engine is the most powerful and reliable engine of our time. At least it’s the most powerful and largest engine ever created and modified for 2021. Of course, there are a lot of Harley Davidson fans who have been waiting for this engine.

In fact, according to some surveys, more than half of the motorcyclists in the United States ride a Harley Davidson as their primary motorcycle. This a high-performance option for all these riders. In particular, this is a bolt-on replacement engine for the 2018 Softail models or later. So, it’s one of the best ways we can upgrade these vehicles.

Motorcycles that were originally equipped with a Milwaukee-Eight engine could deliver high rpm. Also, this engine can not only provide great horsepower but also an excellent torque increase. From cruising speed, torque power is needed to get through a variety of difficult roads. 

Here, the performance is far superior when this new engine is incorporated into compatible Harley Davidson motorcycles. The manufacturer also provides a factory-limited warranty of about 12 months. These riders can get it if they purchase this engine through an authorized Harley-Davidson dealer.

Besides, the manufacturer assures that this is one of the engines with the highest torque and highest power speed as it is what Harley Davidson fans are looking for. In turn, this manufacturer also indicates that the engine meets the highest quality standards. Therefore, the engine provides high performance from the very first moment. 

All these factors are important to have a reliable engine. So, here we must mention the main characteristics of this engine when installed in a Harley Davidson Softail motorcycle. 

Key Features Of Screamin’ Eagle 131

A lot of Harley Davidson fans with the right bike can increase horsepower by 50% as well as torque power. All it takes is one engine change and a day’s work to get this much extra power. However, the best features of this new engine are not only limited to increased power.

1. Compared to the 114 engine, the 131 box engine can offer a wide variety of design and operational changes. In this case, the typical Stage IV Harley Davidson upgrades have been incorporated. These upgrades are complemented by more significant modifications to the entire vehicle’s operation.

2. The intake and exhaust valves are one millimeter larger. This comparison is very evident when we look at the Screamin’ Eagle Milwaukee eight Stage IV kits. Intake and exhaust lobes can also count on a higher lift cam with more lift and longer life. Of course, this feature is highly valued by experienced and fanatical riders.

Additionally, the compression ratio with forged pistons is higher and more efficient. Also, steel sleeve cylinders and a larger 64-millimeter throttle body are incorporated. Along with this throttle body, an intake manifold, and high-capacity fuel, injectors are also included. These injectors can provide 5.5 grams per second of capacity. 

3. On the one hand, the increased displacement is what mostly provides the increase in power that the motorcycle will be able to take advantage of. However, it is also necessary to consider that the flat, wide torque curve is combined with the ability to use that power.

All of this is the result of a more complete and comprehensive engine tuning. That’s why the extra cubic inches can be used to their fullest advantage.

4. Some experts mention that the previous engine had a classic Harley Davidson torque curve. In turn, the typical shed roof meant a peak of 112-pound feet along with 2500 revolutions per minute.

After that at 5500 revolutions per minute, the torque drops to 70 lbs. The smaller diameter intake ports that are useful for reaching the maximum at 2500 revolutions per minute are then insufficient.

5. When it comes to higher RPMs, the torque output drops to almost half of its maximum capacity. So, the new 131 engine arrives to be able to solve this small inconvenience with the motorcycle.

Here, it is a larger engine with larger displacements. So, the maximum torque of 120-pound feet at 1700 revolutions per minute can continue up to 4200 revolutions per minute.

6. This is because the engine has been given a greater breathing capacity at higher RPMs. In particular, this is due to a more aggressive cam and larger ports within the engine. So, it is possible to achieve a much wider range of motorcycle torque power. When it comes to 2800 to 5200 rpm, you can count on more than 120 lbs.

7. Also, maximum torque power can reach a peak of 130.67 lbs. Moreover, from idling to stabilizing speed before the red line, horsepower production is also linear. Here, the increase is constant and very pleasant when it comes to enjoying a great speed. 

8. The maximum power can reach 5620 revolutions per minute with 121.62 horsepower. So, this is a big increase compared to the limit of 4780 revolutions per minute and 81 horsepower of the original 114 engines. 

9. The quarter-mile can also be reached at 12.58 seconds which is one second faster than the 114 engine. Besides, when it comes to reaching 100 miles per hour the 131 engine takes much less time. Beyond that, when it comes to a speed of 0 to 30 miles per hour the time is usually identical between both engines.

Therefore, the additional power of the new 131 engine will begin to be enjoyed at over 40 miles per hour. No doubt, this is a great feature that Harley Davidson fans know how to appreciate. 

Additional Engine Features 131

Some users choose to incorporate Screamin Eagle Street Cannon mufflers into their motorcycles. This way, they can get 124 horsepower and 135-pound feet of torque from the rear wheel. In short, it’s a great power for people who enjoy speed.

Even each of these engines can be highlighted with the 131 Stage IV badge on the timer cover and cylinder heads. Of course, this is a great way to tell other Harley Davidson fans that someone has changed their motorcycle engine. As if that weren’t enough, a selection of two different finish treatments is provided for the new engine.

This way, you can combine a personalized steering system with an original style that is emblematic of this bike. It’s simply a choice of glossy black and black or just black and chrome. Either way, each of these designs can be truly unique for the best fans.

In recent times, it has been known that the manufacturer provides an extended limited warranty of up to 24 months. In turn, people who have purchased a motorcycle of this type have 60 days to obtain an additional benefit.

This way, the new engine purchased will be able to have the same warranty as the vehicle. Otherwise, the new engine will be covered by a 12-month factory-limited warranty.

Here, we can mention the motorcycles that are compatible to install this Screamin’ Eagle Milwaukee-Eight 131 assembled engine.

1. 2018 and later Softail motorcycles

2. Harley Davidson motorcycles touring from 2017 onwards

Also, a budget of $6195 is required to purchase this oil-cooled engine. You can also choose the $6,395 option when it comes to double cooling. Either way, the result is usually more than great as mentioned by those who have purchased this engine. 

Here, it is important to consider that Harley Davidson Trike models are not compatible to use this engine. So, this could be another of the many reasons why users prefer a motorcycle to a tricycle.

Finally, we must consider that this engine meets the emissions and noise standards of most states in the United States. However, these standards do not meet the requirements of California. Furthermore, to obtain a good result, an official Harley Davidson dealer must carry out the installation. 

To obtain a proper installation any Harley Davidson model requires the purchase of some additional components. Here, it might be necessary to purchase ECM recalibration with Screamin’ Eagle Pro Street Tuner. Specific mounting details on each bike may vary considerably.

However, those who have decided to change their motorcycle engine should consider having an appropriate budget. Therefore, replacing some vehicle parts will help you get the most out of your new engine.