Harley Stage 1 Vs. Stage 2 Vs. Stage 3: In-Depth Overview

If you have a Harley Davidson motorbike and want to get an OEM component for it, you might have heard about stage 1 or stage 2 terms. So, what does stage 1, stage 2, or stage 3 mean for Harley bikes? Usually, a stage refers to the performance upgrade and modification of the motorbike components. 

And based on the performance and modification, Harley Davidson has classified its bikes into three categories. They include stage 1, stage 2, and stage 3. Thus, you must know Harley stage 1 vs. stage 2 vs. stage 3 differences to know which modification will work with what bike. 

Stage 1 motorbikes have intake and exhaust upgrades and modifications. Then, stage 2 indicates a 20% to 25% engine performance upgrade from the stock engine. Finally, stage 3 includes all the upgrades of stage 1 and stage 2. It also has a cam engine upgrade with a bigger mild bore. 

Harley Stage 1 Vs. Stage 2 Vs. Stage 3

Harley Stage 1 Vs. Stage 2 Vs. Stage 3

Harley Stage 1 Vs. Stage 2 Vs. Stage 3

Both aftermarket and OEM companies use the term “stage” to refer to different levels of modification and performance elevation of motorbikes. With the stage, you will find which component will find your motorbike and which won’t.  So, what does a stage truly refers to? Let’s see it first. 

What Does Stage Mean In A Motorbike?

When companies manufacture any motorbike, they try a different combination of engines and essential components. It offers different performance levels. Also, following the original manufacturers, various aftermarket sellers combine multiple components to upgrade the motorbike’s performance. 

As the combination of different components elevates the performance of Harley motorbikes, it is named different stages. Also, the stages are applicable for other motorbikes, too, with the upgrade. 

The concept first came into being in the early 1980s. Kerker and K&N offered different component sets for Harley motorbikes and others during this time. This was referred to as the first stage modification for motorcycles. 

Now that we know the main concept of motorbike modification stages, let’s see what the different stages of the Harley motorbike mean. 

Stage 1: Intake, Exhaust, And Tuning Upgrade

Intake, Exhaust, And Tuning Upgrade

Stage 1 works as the foundation of all the later stages for upgrades. It focuses on increasing the general performance and appearance of Harley Davidson motorbikes. Besides the performance and look, stage 1 will also enhance the sound quality of your Harley with a better exhaust system. 

The modification kept the stock engine without any change. However, the modification focused on the intake system, tuning, and exhaust. The main customization includes an EFI tuner that results in better sound quality. You would love the deep sound after the customization. 

After you complete the stage 1 customization of your Harley, you will see a 10% to 15% general performance increase of the stock engine. Although it may not appear highly visible in regular riding, you will feel the smoothness and consistency. 

Some stage 1 modifications include for the 2018 Road Glide version:

  • Stock 107” engine 
  • Jackpot 2/1 exhaust
  • FM AC/DC air cleaner
  • Dynojet Power Vision tuner

Stage 2: Basically, A Cam Upgrade

Once you have laid the foundation with the stage 1 customization of your motorbike, you can try the stage 2 upgrades. The stage 2 kits will let you upgrade the Harley motorbike cam system. So, you will find the right one to suit your riding style and requirement. 

Mainly, two upgrade options are available for the stage t Harley motorbikes. It includes:

  1. Power kit 
  2. Torque kit 

You would see 15% to 20% general performance enhancement with the torque kit. It works best for the low to mid RPM systems. As you improve the torque kit, the throttle will become smoother. So, you find the riding experience crisp and smooth. 

On the other side, a power kit upgrade is also preferable for the low to mid-system RPM range. It delivers around 25% overall enhancement of the performance. It will improve the overall speed. Thus, the stage 2 upgrade of the Harley bike is an adrenaline feeder for fast riders. 

Once you complete the stage 2 customization, you can expect an overall 20% to 25% performance enhancement of the stock engine. So, you will find the performance difference almost immediately as you ride the motorcycle

For the Harley Road Glide 2018 version, stage 2 includes the following upgrades:

  • 117 engine 
  • Wood WM8-222 cam
  • FM AC/DC air cleaner
  • Dynojet Power Vision tune

The intake system can intake and exhaust more air as you modify the air cleaner system. So, it improves the performance. Plus, with the tuning system, you will find the sound of the Harley bike truly amazing. The clutch spring also improves the smoothness of the engine. 

Stage 3: Piston And Big Bore Cylinder Upgrades

Piston And Big Bore Cylinder Upgrades

With the stage 1 and 2 upgrades, your Harley is all set for the ultimate stage 3 upgrades. It includes increased power of the engine and a larger engine displacement capacity. The displacement capacity of the engine improves. Also, you use bigger bores and air cleaner for Harley motorbike. It can hold more fuel and air. 

On top of it, stage 3 also has a higher compression piston. Thus, the piston can squeeze better air and fuel intake. It will deliver incredibly powerful engine performance. It will result in an almost 35% overall performance increase compared to the stock engine. 

Also, you may select the downshift of the motorbike’s free passing engine power. As you can control the downshift system, riding the motorbike is funnier than ever. 

The stage 3 kit upgrade also keeps the previous body for the stock throttle. So, riders can control the bike better. Last but not least, it also includes a mild big bore. It results in better sound. For Road Glide 2018 version, stage 3 upgrades have multiple customization offers.  It includes:

  • 17 big bore kit 10.8 comps, 
  • Wood WM8-222 cam, 
  • FM AC/DC air cleaner, 
  • Heavy-duty clutch springs, 
  • Dynojet Power Vision tuner

You will find improvements in a gasket, cam bearing system, lifter capacity, and clutch components. Thus, the bike goes an almost complete overhauling. 

Point of Consideration

Stage 1

Stage 2

Stage 3

Performance enhancement 

10% to 15% 

20% to 25%

Around 35% 

Main improves 

Stock engine performance, sound, and tuning 

Bore system, engine, and air intake 

Fuel and air intake bore performance and tuner system 

Sound and vibration 

Improves considerably 

Only a slight enhancement 

Not so significant 

Exhaust system 

Gets a massive development 

More focused on engine performance 

Complete overhaul for the best riding experience 

Stage 4 And Stage 5 Developments:

Although Harley engines and motorbikes have the three major stages for customization of the components, you will see stage 4 and stage 5 also. Although they haven’t come into mainstream customization, you need to understand their basics. 

Stage 4 upgrades include an improved cam system and headwork. Also, a few Harley stage 4 upgrades will have injector and throttle body upgrades. On the other side, stage 5 lets you choose a custom and bigger bore for Harley motorbikes. 

The cam becomes more aggressive while the headwork gets comprehensive. It will improve the general performance of a Harley Davidson bike by up to 75%. However, this upgrade isn’t available widely.


Harley stage 1 vs. stage 2 vs. stage 3 discussion shows that you will get a considerable performance boost with each stage. Plus, you will find the sound coming from the exhaust amazing. On top of it, in stages 2 and 3, the motorbike’s fuel and air intake capacity increases massively with a larger bore. So, you will love the smoothness these upgrade kits bring

Last but not least, it ensures your motorbike delivers consistency which makes it reliable. It would be a great benefit for long tours. 

Frequently Asked Questions:

1.Is A Harley Stage 1 Worth It?

Yes, Harley stage 1 is worthier since it lays the foundation for the later upgrades of stages 2 and 3. Also, with 10% to 15% performance enhancement, your riding experience is truly fun. 

2.How Much Is A Harley Stage 3?

The stage 3 Harley customization kit will cost you $1800. It includes stage 3 kits from Screamin’ Eagle Milwaukee with an excellent performance boost. 

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