The information available in most of the manuals about what octane gas for Harley needs is very skimpy. Most of the manuals ask you to use unleaded gas which only means that the gas should have the least amount of lead in it. This goes for all kinds of engines as the lead in the gas only helps to add to atmospheric pollution and does nothing else. The lead in the gas does not get burnt but is emitted into the air thus increasing the lead content suspended into the air that everybody breathes in. Hence using unleaded gas is the most common advice you can get.

It is better to take the suggestion of manuals that specify the type of gas with exact octane content needed for the Harley. The manuals which come with the motorcycle are the best ones for reference but in case you did not get one with your Harley bike, then it is better to get one from your local dealer to find out best octane gas for Harley Davidson, which is appropriate for the type of engine your motorcycle has. The Harleys come with different kinds of engines, and the manufacturer is the best person to suggest the kind of gas to be used depending on the compression ratio.

Worrying about the octane content in the gas you are using for the Harley is not applicable to you if you have a supercharged, turbo-charged engine or an engine with ‘nitrous oxide injection. If you are undecided about the type of gas to run your Harley on and are still very confused about what octane gas should I use in my Harley, then perhaps the following information can dispel some of your doubts. You will be able to judge what gas is best for your motorcycle and how you can get the best out of it in the long run from the following.

Importance of Compression ratio in selection of fuel

The most important factor in choosing the type of gas is the compression ratio of the engine which is either above 10:1 meaning ‘high compression engine’ or below it meaning low compression engine’. This compression ratio usually varies from 11.5:1 to 9.5:1. You may be wondering why this compression ratio is so critical regarding the gas to be used for the Harley. The fact is that the octane gas for Harley in its engine cylinder of the motorcycle has to get ignited for it to expand and provide the power for the movement. Before the gas is ignited it gets compressed by the upward flow in the cylinder.

When the gas gets compressed by the piston, it can also get ignited by the pressure before the spark plug provides the spark to ignite it which is known as ‘pre-ignition.’ This upsets the timing of the piston movement which has to travel some more before the gas should have become ignited by the spark. As a result, the detonation of the gas creates a downward pressure on the piston traveling upwards and is yet to reach its highest point of the trip. The opposing two forces cause the engine to knock and produce pinging noises. It happens mostly during acceleration when more gas is fed into the cylinder to produce more power.

The role of octane in the gas now becomes evident as it can resist this ‘pre-ignition’ detonation. The higher the octane content the higher is the amount of compression that an engine can achieve before the detonation. You can know the percentage of octane content in the gas by the numbers assigned to it which is the proportion. Figures are available for three types octane content such as ‘Regular’, ‘Plus’ and ‘Premium’.  For the ‘Regular’ type of gas the figure is 85 to 87, for the ‘Plus’ type it is 88 to 89 and for the ‘ Premium’ type it is 90 to 93.

Lower octane content will help to get more power as it gets ignited quickly but it can cause an imbalance in the engine which can be disastrous for it in the long run. Most of the manufacturers suggest that you use gas with high octane gas for Harley to make sure that the engine does not overheat or cause any knocking when driving your Harley. Another reason behind the manufacturer’s suggestion to use gas with high octane content is to stop the buyer from bringing their Harley in for costly repair which is solvable by a change in the type of gas used.

What is the highest compression ratio for 93 octane

A compression ratio of 10.5:1 is generally considered to be the highest that can be used with 93 octane fuel. Higher ratios may be possible with other types of fuel or modifications to the engine, but they can also lead to reduced performance and increased wear and tear.

Some Misconceptions about Premium Gas

It is not true that you have to use gas with the highest octane content always which is the biggest misconception that owners of Harleys usually have. Using your ear while driving the motorcycle can be an excellent way to find out whether the type of gas you are using is suitable for your bike or not. If the engine of your Harley knocks or pings too much, just replace the gas in the tank with one having higher octane content and you will feel the difference. Settle on the type that helps your motorcycle to perform the best.

Can I use octane booster in my Harley-Davidson?

You should always be careful about another thing while using your Harley motorcycle. Always try to avoid octane boosters which are available at various auto stores as much as possible. These boosters do boost the octane percentage in the gas and provide the engine with more power, but it is of a temporary nature only. People who are involved in racing use the octane booster which is supposed to be avoided in normal driving. These boosters do more harm than good which every Harley owner wants to run his motorcycle smoothly for ages should keep in mind. Simply remember that ‘octane boosters’ are for ‘racers.’

What Type Of Fuel Should You Use On A Harley?

When it comes to fuel for your Harley, you have two main options: regular fuel or premium fuel.

  • Regular fuel is fine for most Harleys and will give you an octane rating of 85-90.
  • Premium fuel has an octane rating of 91-95 and is recommended for Harleys that require it or those that are used for racing.

So, what’s the difference?
Well, regular fuel is a bit cheaper and gives your engine a little less wear and tear.
Premium fuel, on the other hand, helps your engine run cooler and cleaner – which can be important if you do a lot of riding or use your bike for racing.

What Are The Benefits of Premium Fuel?

For starters, using premium fuel can help your bike run more smoothly. It also helps to keep your engine cooler, which can prolong the life of your bike. Additionally, using premium fuel can make your bike more responsive and give you better performance.

Ultimately, it’s up to you whether or not you want to use premium fuel in your Harley. But, if you’re looking for better performance and longer engine life, then premium fuel may be right for you. Here are the some of the benefits of using premium fuel for your harley.

1. Higher octane ratings

Does using a premium fuel make a difference in your bike? The answer to this question is actually yes – using a higher-quality fuel can result in improved performance for your motorcycle. This is because the higher octane rating of premium fuels helps to prevent “knocking” or “pinging” during combustion, which can cause damage to your engine over time.

2. Better performance

There are a lot of people that believe that using premium fuel in a Harley Davidson will result in better performance. This is because the engines in Harleys are designed to run on high octane fuel. When you use regular unleaded gasoline, it won’t run as smoothly and it can also cause damage to your engine over time. If you want your bike to run at its best, you should always use premium fuel.

3. Lower emissions

The Harley davidson motorcycle is a popular choice for riders looking for a powerful and stylish bike. While these bikes are known for their impressive performance, they also produce emissions that can be harmful to the environment. However, using a premium fuel in your Harley davidson can help reduce these emissions.

Premium fuel is designed to produce lower emissions than traditional gasoline. By using this fuel in your Harley davidson, you can help reduce the amount of pollutants released into the air. In addition to helping the environment, using premium fuel can also improve your bike’s performance.

So, if you want to do your part to reduce emissions and keep your bike running at its best, consider using premium fuel in your Harley davidson. It’s an easy way to make a big difference for the environment and for your ride.

4. Improved fuel economy

There’s no doubt that Harley-Davidson motorcycles are unique and stylish vehicles, but they also require premium fuel in order to run properly. Using anything less can lead to poor fuel economy and performance issues. However, many riders are unaware of this and end up using lower quality fuel, which can be costly and damaging in the long run.

5. Fewer deposits and carbon buildup

A recent study has shown that using premium fuel in Harley Davidson motorcycle engines results in fewer deposits and carbon buildup. The study was conducted by a team of engineers from the University of Wisconsin-Milwaukee. 

The team tested two identical Harley Davidson motorcycles, one with a standard engine and one with a high-performance engine. Both motorcycles were ridden under the same conditions, and the only difference was the type of fuel used. The study found that the high-performance engine had significantly less carbon buildup and deposits than the standard engine. 

The study’s authors suggest that using premium fuel in Harley Davidson engines may help to reduce carbon buildup and improve performance. They also recommend that riders consult their motorcycle dealer to see if they offer a premium fuel blend specifically designed for Harleys.

6. Longer engine life

The best way to keep your Harley Davidson engine running smoothly and prevent any premature wear is by using premium fuel. Using a higher octane fuel than the one recommended by the manufacturer can actually result in longer engine life. The truth is that most engines are designed to run on a regular grade fuel, but by using a higher octane fuel you can actually minimize the risk of knocking and pinging, which can cause damage over time. In addition, premium fuels also contain detergents and other additives that help keep your engine clean and lubricated, resulting in longer engine life.

Frequently Asked Questions (FAQs)

What gas should I run in my Harley?

Motorcycle engines, including all current Harley-Davidson engines, require 91 octane or higher. Most engine manufacturers specify a minimum octane rating requirement for fuel. The higher the octane rating of the fuel, the less chance there is of “knocking” or “pinging” during combustion. This knocking can cause engine damage over time, so it’s important to use the correct fuel for your bike.

Can you run 93 octane in a Harley?

Yes, you can put 93 octane in your Harley. However, you don’t need to put high octane fuel in your Harley. You can put regular unleaded gasoline in your Harley and it will run just fine.

How many cc is a 88 cubic inch Harley motor?

The Harley-Davidson 88 cubic inch engine is a 1,450 cc powerhouse that delivers plenty of torque and power. This engine is perfect for riders who want the classic Harley sound and feel, without sacrificing any performance. Thanks to its displacement, this engine is capable of reaching speeds of up to 90 mph.

Can I put 110 octane in my Harley?

No, you can’t put 110 octane fuel in your Harley Davidson. You should only put in the recommended fuel for your bike, which is usually a mid-grade or high-grade fuel. Putting in a higher octane fuel than what is recommended could damage your engine and void your warranty.

Can I run regular gas in my Harley?

The truth is, there is no one definitive answer to this question.  It depends on the make and model of your Harley, as well as the type of gas you use.  In most cases, it’s best to stick with the higher octane fuel recommended by the manufacturer.

What type of gas should I put in my iron 883?

Iron 883 riders have several options when it comes to the type of gas they put in their bikes. Some riders may choose to use a lower octane gas in order to save money, but this can be harmful to the engine.
Riders who are looking to get the most out of their bike should use a 91 or higher octane gas. This will help the engine run smoothly and prevent any damage from occurring.

Should I run premium gas in my Harley?

Owners of Harley-Davidson fuel-injected models are being advised to use premium unleaded gasoline. The company says that using anything less could cause damage to the engine. This is due to the high compression ratio of the engines in these motorcycles.

What is the best octane booster for Harley-Davidson?

You should consider using Screamin’ E octane booster. One four-ounce bottle of Octane Boost treats one motorcycle tank of fuel, and it is safe for use with catalyst and oxygen sensor equipped bikes.

What happens if you put the wrong gas in your motorcycle?

If you put the wrong gas in your motorcycle, you will likely notice a decrease in horsepower until you get the proper fuel back in the bike. This, of course, is not ideal, but at the same time it’s not the end of the world. Most motorcycles can run on different types of fuel, but they won’t run as well as they should.


The above information will surely provide an answer to what octane gas should I use in my Harley and keep your Harley running for a long time and give you maximum driving satisfaction.

Wish you happy travel with your Harley.