10 Major Types of Harley-Davidson Engines [Comparison]

Without further ado, the ten most significant V-Twin engine generations in Harley’s lineup since 1903 are as follows:

F-Head
Flathead
Knucklehead
Panhead
Ironhead
Shovelhead
Evolution (Blockhead)
Twin Cam
Revolution
Milwaukee Eight (Wafflehead)

If you want to find out more about these legendary power sources, you’ve come to the right place.

We at PowerSportsGuide have compiled all you need to know under one roof!

Contents show

What Kind of Engines do Harleys Have?

There’s no question that one of the most distinguishing features of Harley-Davidsons is their unique V-twin engine. The vast majority of these engines have the classic 45-degree cylinder architecture and come with many traditional features like carburetors and air cooling.

Their long-stroke/small bore configuration produces less HP but more torque than other motorcycle engines.

The key features of traditional Harley Big-Twin engines are as follows:

2 cylinders
45° V-twin architecture (60° on Revolution models)
Long-stroke/small bore cylinder configuration
Longitudinal engine location
Carburetion: carburetors
Air-cooling
Displacements: 45-131 cubic inches
HP ratings: 11-121 HP
Single pin crankshaft

These unique features cause the cylinders to fire at uneven intervals, which translates to the unbeatable “potato-potato-potato” sound.

The first Big-Twin Harley engine, the F-Head hit the market in 1911. Since then, these power mills have undergone many generations, which were as follows:

Harley-Davidson Engine Chart

Year	Engine	Sizes (ci)
1911-1929	F-Head	61,74
1929-1973	Flathead	45, 54, 74, 80
1936-1947	Knucklehead	61, 74
1948-1965	Panhead	61, 74
1957-1985	Ironhead	45
1966-1984	Shovelhead	74, 80
1984-1999	Evolution (Blockhead)	80
1999-2016	Twin Cam	88, 96, 103, 110
2001-2017	Revolution	69,76
2017-	Milwaukee Eight (Wafflehead)	107, 114, 117, 131

Let’s get down to the nitty-gritty and talk about these engines in detail!

10 Major Types of Harley-Davidson Engines

1. Harley F-Head Engines

What is a Harley F-Head engine?

The F-Head big-twin is considered the first commercially-successful V-twin engine from Harley-Davidson. Due to its design, it was often referred to as a Pocket Valve or Intake Over Exhaust (IOE) engine.

The predecessor of this engine was the first Harley V-twin with atmospheric valves. This 49.5-cubic inch, 4-stroke, 7 HP, twin engine was built by doubling the cylinders of the proven 27” (440cc) single-cylinder F-Head.

Unfortunately, this first attempt failed since it utilized atmospheric-controlled intake valves that caused many problems.

To fix this issue, the engine was upgraded with mechanically controlled valves and its displacement was increased to 61 cubic inches (812cc).

The new power source debuted in the 1911 Harley-Davidson Model 7D and was used in many commercial and police motorcycles over the years.

By 1922, Harley released its bigger brother, the 74 cubic-inch (1212.6cc) F-Head V-twin.

In which years did Harleys have F-Heads V-twin engines?

Harley-Davidson offered its motorcycles with F-Head V-twin engines from 1911 through 1929.

Which Harley engine came before the F-Head?

The commercially-successful F-Head V-twin was based on the 27” single-cylinder F-Head engine.

The first version of this engine was the 1909 “atmospheric V-Twin” that had mechanically-controlled valves and a larger (61”) displacement for the 1911 model year.

What motor came after the F-Head?

The outdated F-Head engine was replaced by the Flathead series in 1929.

What size was a Harley F-Head engine?

The sizes of Harley F-Head engines averaged from 26.8 up to 74 cubic inches:

Harley-Davidson F-Head 26.8 ci Single
Harley-Davidson F-Head 49.5 ci (atmospheric valve) V-Twin
Harley-Davidson F-Head 61 ci V-Twin
Harley-Davidson F-Head 74 ci V-Twin

Which Harley has an F-Head engine?

Harley used its popular F-head V-twin engines in many motorcycles, including:

911 Harley-Davidson 7D
1915 Harley-Davidson 11F
1916 Harley-Davidson J
1918 Harley-Davidson 18-J
1918 Harley-Davidson F
1920 Harley-Davidson 20-J
1925 Harley-Davidson JD

2. Harley Flathead Engines

What is a Harley Flathead engine?

The Flathead engine replaced the outdated F-head V-twin line in the 1929 season. It was also known as the “Flatty” or “Sidevalve” engine since the valves were mounted on the side of the cylinders instead of on top.

This simple removable head combined with the side valves reduced the engine’s complexity, which translated to easier serviceability.

The first engine in this breed was the Flathead 45ci debuted in the DL model, which was also carried over to the RL model.

In the following decades, the Flathead family was expanded with some larger brothers including the 54, 74, and 80 cubic-inch configurations. Unfortunately, none of these were long-lived or as reliable as the original 45.

Pros of Flathead engines:

Simple design
Fewer parts
One-piece cast metal heads
Easy to service

Cons of Flathead engines:

“Breathing issues” (the airflow had to make a 90° turn to enter the cylinders)
Prone to overheating under heavy use
Limited ability to overbore the cylinders
Total-loss lubrication system

Why is it called a Flathead engine?

As the name suggests, Flathead engines came with completely flat cylinder heads, which were often made of one piece of casted metal. Since the valves were moved to the side of the cylinders, they didn’t protrude from the head.

Due to this new design, Flathead engines were also often called “Sidevalve” engines.

What year did Harley-Davidson come out with the Flathead engine?

Harley introduced its first 45 ci Flathead engine on the 1929 D Model.

What years were Harley Flatheads made?

Flathead engines were in production from 1929 through 1973.

Although the more modern Knucklehead engines were revealed in 1936, the Flathead 80 remained in the lineup in 1942 while the Flathead 74 was discontinued after the 1974 season.

The more popular small-inch Flatheads disappeared from 2-wheeled Harley motorcycles in the mid-1950s, but they were kept as the power source of the three-wheeled Harley “Servi Car” until 1973.

The latter was a utility Harley trike, commonly used by mobile vendors, small businesses, and the police.

Which Harley engine came before the Flathead?

The predecessor of the Harley Flathead was the F-head engine family.

Which motor came after the Flathead?

Flathead engines were replaced by the more advanced Knucklehead engine series.

What sizes did the Harley Flathead engine come in?

The Harley Flathead engine was available from 45ci to 80ci and sizes in between:

Flathead 45” (737cc)
Flathead 54” (883cc)
Flathead 74” (1200cc)
Flathead 80” (1300cc)

How many Flatheads did Harley make?

Harley Flathead engines were produced in pretty large quantities. For example, the manufacturer built more than 60,000 Flathead 45s just for the American forces during WWII.

Which Harleys had a Flathead engine?

(Examples)

1929 Harley-Davidson D 45
1930 Harley-Davidson VL
1932 Harley-Davidson R
1935 Harley-Davidson VLH
1937 Harley-Davidson W
1944 Harley-Davidson WLA
1944 Harley-Davidson WLC
1952 Harley-Davidson K
1952 Harley-Davidson KR
1956 Harley-Davidson HK
1956 Harley-Davidson U
1956 Harley-Davidson UL
1956 Harley-Davidson ULH
1956 Harley-Davidson UH
1932 Harley-Davidson Servi-Car

3. Harley Knucklehead Engines

What is a Harley Knucklehead engine?

The Knucklehead engine was introduced in 1936 as the replacement for the Flathead engine. (However, the latter remained in the lineup until 1973.) This two-cylinder, 45-degree V-twin power mill featured two valves per cylinder.

The Knucklehead was the first Harley Big Twin with pushrod actuated overhead valves (OHV), engineered by Bill Harley.

It was available in two sizes, the 61ci (983cc) and the 74ci (1212cc) variations.

Pros of Knucklehead engines:

Pushrod actuated overhead valves
Two valves per cylinder
Circulating oil lubrication system
More engine power
Less fuel consumption

Why is it called a Knucklehead engine?

The Knucklehead engine was nicknamed for its rocker boxes, which were shaped like human knuckles. These polished alloy rocker boxes were mounted on top of each cylinder.

Referring to its overhead-valve configurations, these engines were also referred to as “OHVs.”

What year did Harley-Davidson come out with the Knucklehead engine?

The first Knucklehead engine hit the marketplace in 1936 on the Harley-Davidson EL “Knucklehead” model.

In which years were Harley Knuckleheads made?

Knucklehead engines were manufactured for 12 model years, from 1936 through 1947.

Which Harley engine came before the Knucklehead?

The predecessor of the Knucklehead engine was the outdated Flathead.

Which motor came after the Knucklehead?

The Panhead engine replaced the Knucklehead family in 1948.

What size was the Harley Knucklehead engine?

Harley’s Knucklehead engine was available in two displacements, the 61 ci, and 74 ci configurations.

Was the Knucklehead a good engine?

Yes, it’s safe to say that Knucklehead engines were considered a good power source in their time. They were known for their great power and fuel economy, as well as their clean circulating oil system.

How many Knuckleheads did Harley make?

According to NewAtlas.com, more than 41,000 Harley-Davidson Knucklehead motorcycles were produced in the ‘30s and ‘40s.

Which Harleys had a Knucklehead engine?

(Examples)

1936 Harley-Davidson E Knucklehead
1936 Harley-Davidson EL Knucklehead
1940 Harley-Davidson ES Knucklehead
1936 Harley-Davidson VL Knucklehead
1947 Harley Davidson FL Knucklehead

4. Harley Panhead Engines

What is a Harley Panhead engine?

The Harley Panhead is a two-cylinder, 45-degree V-twin engine offered in displacements of 61 ci (model: EL) and the larger 74 ci (models: FL, FLH).

It shared its bottom end with its predecessor but came with many advanced features including aluminum heads, internal oil lines, pushrod-controlled overhead valves (2 per cylinder), and hydraulic valve lifters.

The Panhead engine family replaced the deservedly-popular Knucklehead engine in the 1948 season and remained in the fleet until 1965.

Through its lifecycle, the Panhead went through over six upgrades, some of which resulted in a noticeable horsepower increase.

Many riders claim that the most attractive Big Twin engine from Harley was the Panhead!

Why was it called a Panhead engine?

The Panhead engine got its name for its dishpan-shaped rocker cover boxes.

Why were Panheads so popular?

Panhead engines were widely popular for their great torque, durability, and easy-to-maintain design. They also had a unique appearance and generated an unbeatable sound!

In which years were Harley Panhead engines made?

Panhead engines were produced from 1948 through 1965 when they were replaced by the more advanced Shovelhead.

Which Harley engine came before the Panhead?

The Knucklehead is considered the predecessor of the Panhead engine.

What motor came after the Panhead?

Harley replaced the Panhead with the Shovelhead engine family in 1965.

What sizes did the Harley Panhead engine come in?

The Panhead engine was available in the displacements of 61 ci (model: EL) and 74 ci (models: FL, FLH).

Which Harleys had the Panhead engine?

(Examples)

1948 Harley-Davidson FL Panhead
1948 Harley-Davidson EL Panhead
1952 The Harley-Davidson Hydra-Glide Panhead
1956 Harley-Davidson FLH Panhead
1958 Harley Davidson FLH Duo Glide Panhead
1965 Harley-Davidson Electra Glide FL FLH Panhead

5. Harley Ironhead Engines

What is a Harley Ironhead engine?

The Harley Ironhead represents a unique category in this list since this engine is not considered a major Big-Twin generation. Instead, it was offered during the eras of Panhead and Shovelhead engines, from 1957 through 1985.

The Ironhead was a two-cylinder, two valves per cylinder, 45-cubic-inch V-twin specifically developed for Harley-Davidson Sportster models.

Why was it called the Ironhead engine?

As the name implies, the cylinder heads of the Ironhead engine were made of iron instead of aluminum.

In which years were Harley Ironheads made?

Harley-Davidson offered its Ironhead engines from 1957 to 1985.

What size was a Harley Ironhead engine?

The Harley Ironhead was a 45 cubic inch (750cc) engine.

Which Harleys had an Ironhead engine?

The Ironhead engine was reserved exclusively for the Sportster models.

6. Harley Shovelhead Engines

What is a Harley Shovelhead engine?

The new Shovelhead engine made its debut in 1966. It was designed to be lighter and more powerful to counterbalance the weight increase of the new Harley motorcycles.

Shovelhead engines were available in displacements of 74ci and 80ci.

While this power source had some issues at the beginning of its career, after some improvements it become popular among riders and this translated to better sales figures.

These upgrades increased not only the engine power but also improved the cooling and lubrication systems as well.

Early models only featured 10 cooling fins, which proved to be inefficient for their large cylinders. The poorly designed oil system also contributed to overheating issues and allowed oil to leak into the valves.

These issues dramatically increased oil consumption and decreased performance. In the worst-case scenario, these malfunctions ended in severe engine damage!

Why was it called the Shovelhead engine?

Just like its predecessors, the Shovelhead engine got its nickname from the design of its rocker cover boxes, which were shaped like small coal shovels.

In which years were Harley Shovelheads made?

Harley-Davidson produced motorcycles with Shovelhead engines from 1966 until 1984.

Which Harley engine came before the Shovelhead?

The predecessor of the Shovelhead was the Panhead engine.

Which motor came after the Shovelhead?

The Shovelhead was succeeded by the Evolution engine series in 1984.

What sizes did the Harley Shovelhead engine come in?

The Harley Shovelhead engine was marketed with displacements of 74 cubic inches and 80 cubic inches.

Which Harley had the Shovelhead engine?

1978 Harley-Davidson 74” FLH Shovelhead
1978 Harley Davidson FXE 1200 Super Glide Shovelhead
1984 Harley-Davidson FXWG-80 Wide Glide Shovelhead

7. Harley Evolution (Blockhead) Engines

What was the Harley Evolution engine?

The Evolution was a major engine generation of Harley-Davidson manufactured from 1974 through 1999. Compared to the Shovelhead, the Evolution was technically far superior in many ways.

This was no surprise since it was the first Harley engine designed with Computer-Aided Design (CAD).

Thanks to its innovative features and design, Evolution engines ran smoother and cooler and produced more power than their predecessors.

The original Evolution Big Twin was an 80 cubic-inch (1343cc) model that was available until 1999.

For some reason, the manufacturer uses the “Evolution” label on many newer Sportster engines that displace 54, 67, and 74 cubic inches.

However, when riders talk about the Evolution engines, they often refer to the original Big Twin Evolution 80.

Why was it called the Evolution engine?

It’s a lesser-known fact that the Evolution engine was the first Big Twin engine to be named by the manufacturer.

But what about the names of the previously discussed “Heads” engine?

Interestingly, these names were only nicknames given by enthusiasts! Using the analogy of previous names, Evolution engines earned the nickname “Blockheads” due to their squarish cover boxes.

However, this engine was also often referred to as simply “EVO”.

In which years were Harley Evolutions made?

The original 80 cubic-inch Evolution engine was in production from 1984 to 1999.

Which Harley engine came before the Evolution?

The predecessor of the Evolution engine was the Shovelhead.

Which motor came after the Evolution?

The successor of the Evolution engine was the Twin Cam, introduced in 1999.

What sizes did the Harley Evolution engine come in?

The original “Big Twin” Evolution engine was the 80ci (1343cc) V-twin, but over the years many smaller Evolution engines appeared in the Sportster including the Evolution 54, 67, and 74ci models.

Which Harleys had an Evolution engine?

The Evolution Big Twin was nestled in many Harley-Davidson motorcycles such as the Softail, Dyna, FXR, and Touring models. However, they were also used in the FXR2, FXR3, and FXR4 models around the Millennium.

8. Harley Twin Cam Engines

What is a Harley Twin Cam engine?

By 1999, the all-new Twin Cam engine family was revealed with the introduction of the 88 cubic inch model.

Although it was 8ci bigger than its largest predecessor, the Twin Cam 88 was the smallest member of its family! Its larger brothers were the 96, 103, and 110 cubic inch models.

Each of them featured two chain-driven overhead camshafts (DOHC) and produce more horsepower and torque than the Evolution series.

What’s more, they were the first Harley-Davidson engines that were marketed with an optional fuel injection system.

A lesser-known variant of this line was the Twin Cam 88B, which was a counter-balanced 88 cubic-inch Twin Cam, modified to fit in Softail models.

Why was it called a Twin Cam engine?

The name “Twin Cam” refers to this engine’s double overhead camshafts (DOHC) configuration.

What’s the difference between Twin Cam and Evolution Engines?

Compared to the Evolution, the Twin Cam engine came with many innovative features including double overhead camshafts, a more advanced internal twin-gerotor oil pump, and a dual-coil ignition system.

Thanks to these features, the Twin Cam had higher compression and more engine power.

In which years were Harley Twin Cams made?

Harley-Davidson Twin Cam engines were produced from 1999 through 2016.

Which Harley engine came before the Twin Cam?

The predecessor of the Twin Cam engine was the Evolution engine.

Which motor came after the Twin Cam?

The Twin Cam engine was replaced by the Milwaukee Eight engine.

What sizes did the Harley Twin Cam engine come in?

The Twin Cam engine was offered in four displacements, including:

Twin Cam 88 ci
Twin Cam 96 ci
Twin Cam 103 ci
Twin Cam 110 ci

Which Harleys had a Twin Cam engine?

(Examples)

2000 Harley-Davidson Heritage Softail
2000 Harley-Davidson Springer Softail
2000 Harley-Davidson Fat Boy
2000 Harley-Davidson Night Train Softail Deuce
2000 Harley-Davidson Standard
2000 Harley-Davidson Custom

9. Harley Revolution Engines

What is the Harley Revolution engine?

Unlike traditional air-cooled, 45-degree V-twin Harley engines, the all-new Revolution engine line came with innovative liquid cooling, fuel injection, and a 60-degree V-twin cylinder arrangement.

This engine was used on the “muscle” Harley-Davidson models including the V-Rod, Street Rod, Night Rod, and the VRSC models.

The first Revolution power mill was the 2001 69 cubic inch engine, which was extended with a 76 cubic inch sibling in 2008.

Thanks to their short stroke/big bore cylinder architecture and dual overhead camshafts, Revolution engines were capable of revving up to 8,000-9,000 RPMs.

These high revolutions translated to an amazing engine power of 125-165 HP depending on the model.

Why was it called a Revolution engine?

True to its name, Revolution engines packed many revolutionary innovations such as liquid cooling, fuel injection, and a unique 60-degree V-twin configuration.

In which years were Harley Revolution engines made?

Harley-Davidson manufactured its liquid-cooled Revolution engines from 2001 through 2017.

Which Harley engine came before the Revolution?

The predecessor of the Revolution engine was the Twin Cam family.

Which motor came after the Revolution?

Revolution engines were replaced by the Milwaukee Eight series for the 2017 season.

What sizes does the Harley Revolution engine come in?

Harley-Davidson offered its Revolution engine with displacements of 69ci and 76ci.

What Harley has a Revolution engine?

(Examples)

Harley-Davidson VRSCDX Night Rod Special
Harley-Davidson VRXSE V-Rod Destroyer
Harley-Davidson VRSCX V-Rod
Harley-Davidson VRSCF V-Rod Muscle
Harley-Davidson VRSCAW V-Rod
Harley-Davidson VRSCA V-Rod
Harley-Davidson VRSCR Street Rod
Harley-Davidson VRSCSE Screamin’ Eagle CVO V-Rod

10. Harley Milwaukee Eight Engines

What is the Harley Milwaukee Eight engine?

The Milwaukee-Eight family is the ninth generation of Harley-Davidson’s Big Twin engines. These power mills are SOHC, 45-degree V-twins, which are available from 107 to 131ci, and sizes in between.

Certain models are available in both air and liquid-cooled configurations.

Compared to their predecessors, the key advantages of Milwaukee-Eight engines are as follows:

More power and torque
Bigger displacements
4 valves per cylinder (total: 8 valves)
SOHC (single overhead camshaft)
Internal counterbalancers for reduced vibration
Two spark plugs per cylinder
Improved cooling with a heat management system

Why is it called the Milwaukee Eight engine?

The name “Milwaukee Eight” comes from two different sources, Milwaukee commemorates the birthplace of Harley-Davidsons, while the figure “Eight” refers to the number of valves.

In keeping with the analogy of names of previous engines, the Milwaukee-Eight earned the nickname “Wafflehead”. The origin of this name is the design of the engine’s valve covers, which are shaped like waffle irons.

In what year did the Milwaukee Eight engine come out?

Milwaukee Eight engines were released in 2016 for the 2017 model year.

Which Harley engine came before the Milwaukee Eight?

Before the Milwaukee Eight, Harley-Davidson motorcycles were available with Revolution and Twin Cam engines.

What sizes does the Harley Milwaukee Eight engine come in?

Milwaukee Eight engines are available in four different displacements, including:

Milwaukee-8 107ci (1750cc)
Milwaukee-8 114ci (1870cc)
Milwaukee-8 117ci (1920cc)
Milwaukee-8 131ci (2147cc)

Are all Milwaukee Eight engines water cooled?

The Milwaukee Eight engine is available in both liquid and air cooling configurations.

Which Harley has a Milwaukee Eight engine?

(Examples)

2017 Harley Davidson CVO Limited
2017 Harley Davidson CVO Street Glide
2017 Harley Davidson Street Glide
2017 Harley Davidson Street Glide Special
2017 Harley Davidson Road Glide
2017 Harley Davidson Road Glide Special
2017 Electra Glide Ultra Classic
2017 Harley Davidson Road King
2017 Harley Davidson Road King Classic
2017 Harley Davidson Freewheeler
2017 Harley-Davidson Ultra Limited
2017 Harley-Davidson Ultra Limited Low
2017 Harley-Davidson Road Glide
2017 Harley-Davidson Tri Glide

Takeaway – FAQs About Harley Engines

As a takeaway, we’ve answered some of the most common questions about Harley-Davidson engines!

What are the various sizes that Harley engines come in?

The size of Harley-Davidson engines varies between 27.4ci (449cc) and 131ci (2147cc). To be more precise, the most common V-twin Harley engine displacements are as follows:

45ci
54ci
61ci
69ci
74ci
76ci
80ci
88ci
96ci
103ci
107ci
110ci
114ci
117ci
131ci

Regarding “modern” Harley-Davidsons, you can expect their engines to be in the ballpark of 70-131ci.

What’s the biggest engine Harley-Davidson makes?

The biggest Harley-Davidson engine ever built by the factory is the Milwaukee Eight 131 (2147cc).

What’s the smallest engine Harley-Davidson has ever made?

The smallest Harley-Davidson was the 1965 M50 moped powered by a 50cc, two-stroke, single engine. However, this power mill was manufactured by an outside engine supplier (Minarelli).

Regarding modern V-twin configurations, the smallest Harley V-twin was the Revolution X. This liquid-cooled 60-degree V-twin only displaced 30 cubic inches (494cc) and was available on the Harley-Davidson Street 500.

What’s the difference between a Twin Cam and a Milwaukee Eight?

Milwaukee Eight is considered the successor of the Twin Cam engine line. These new power sources are bigger, more powerful, and pack a set of innovative features, including:

Bigger displacements
4 valves per cylinder (total: 8 valves)
SOHC (single overhead camshaft)
Internal counterbalancers for reduced vibration
Two spark plugs per cylinder
Improved cooling with a heat management system

How many cc is a Harley 45 cubic inch engine?

The Harley 45 engine features a displacement of 472cc.

How many cc is a Harley 54 cubic inch engine?

The Harley 54 engine features a displacement of 883cc.

How many cc is a Harley 61 cubic inch engine?

The Harley 61 engine features a displacement of 1000cc.

How many cc is a Harley 74 cubic inch engine?

The Harley 74 engine features a displacement of 1208cc.

How many cc is a Harley 80 cubic inch engine?

The Harley 80 engine features a displacement of 1310cc.

How many cc is a Harley 82 cubic inch engine?

The Harley 82 engine features a displacement of 1340cc.

How many cc is a Harley 88 cubic inch engine?

The Harley 88 engine features a displacement of 1450cc.

How many cc is a Harley 96 cubic inch engine?

The Harley 96 engine features a displacement of 1584cc.

How many cc is a Harley 103 cubic inch engine?

The Harley 103 engine features a displacement of 1690cc.

How many cc is a Harley 107 cubic inch engine?

The Harley 107 engine features a displacement of 1750cc.

How many cc is a Harley 110 cubic inch engine?

The Harley 110 engine features a displacement of 1800cc.

How many cc is a Harley 114 cubic inch engine?

The Harley 114 engine features a displacement of 1870cc.

How many cc is a Harley 117 cubic inch engine?

The Harley 117 engine features a displacement of 1920cc.

How many cc is a Harley 117 cubic inch engine?

The Harley 131engine features a displacement of 2147cc.

Which engine is the Harley 103?

The Harley 103 is a Twin Cam V-twin engine displacing 103 cubic inches. This power source was offered with both air and liquid-cooled configurations.

What is the difference between Harley 103 and 103 high output?

The Harley 103 high output comes with a liquid-cooling system, more cam lift, and an advanced better-flowing airbox. Thanks to these features, it has about 10 percent more torque than the standard air-cooled 103 engine.

Did Harley ever make a 2 stroke engine?

It’s a lesser-known fact that Harley-Davidson manufactured 2-stroke engines in the ‘40s. One of the 2–stroke Harley-Davidsons was the 1948 Model 125 (S-125) featuring a 125cc, 3 HP power source.

The 1965 Harley-Davidson M50 moped was also powered by a 2-stroke single, but the manufacturing of its engine was outsourced to Minarelli.