Understanding how the reserve on a motorcycle works is important for all riders—especially if they do not want to have to push their motorcycle because it has run out of fuel.
This is why one of the important questions that every rider should have a clear answer to is exactly how far their motorcycle can go when on reserve.
How far can a motorcycle go on reserve? How far a motorcycle can go on reserve is determined by the motorcycle’s fuel consumption and reserve capacity. Most motorcycles have an mpg between 35 to 60 and reserve capacity between 0.25 to 0.90 gallons. This means that motorcycles can go between 9 to 55 miles on reserve.
There are some misconceptions and caveats here that need to be mentioned in order to clear out any confusion. Below I go into more detail about everything you need to know about how far you can go on reserve.
What determines how far a motorcycle can go on reserve?
How far a motorcycle can go on reserve will depend on the motorcycle and its fuel tank’s capacity. If in doubt, always refer to your owner’s manual, which should have detailed information about your motorcycle’s fuel tank capacity, including how much fuel is in the reserve.
The mpg of the motorcycle
On average, motorcycles get between 35 to 60 mpg. Of course, that number will vary drastically depending on the motorcycle type and how it is ridden.
Some motorcycles will just be a lot less efficient than others. And riding a motorcycle at low, cruising speeds burns less fuel than pushing it to higher speeds.
Make sure you have a good general idea of your motorcycle’s mph at various speeds so that you can always make an educated estimate.
The reserve capacity
The amount of fuel in the reserve tank will vary between the different motorcycles. Generally, motorcycles will have a reserve fuel capacity between 0.25 to 0.9 gallons.
To find the exact numbers for your motorcycle, please refer to your user manual, which should have information about your motorcycle’s reserve capacity.
How to find how far a motorcycle can go on reserve?
Basically, you need to know how much fuel you have in the reserve tank and how much fuel your motorcycle uses to get how far it will get.
To find your motorcycle’s mpg, use the following formula:
MPG = distance (in miles) / average gas consumption (in gallons).
Then you need to find how much fuel there is in the reserve, which should be easily found in the owner’s manual. Write down the capacity (in gallons) of the motorcycle’s reserve.
To find how far a motorcycle can go on reserve, use the following formula:
Distance (in miles) = MPG × gas in reserve tank (in gallons)
Let’s see how we can use these formulas with a practical example. For example, let’s use the averages (mentioned above) that apply to the average motorcycle to find how far an average motorcycle can travel on reserve.
Since motorcycles have an average mpg between 35 to 60 and an average reserve capacity between 0.25 to 0.9 gallons we have the following two equations
Distance (in miles) = 35 mpg × 0.25 gallons
= 8.75 miles, and
Distance (in miles) = 60 mpg × 0.90 gallons
= 54 miles.
As we can see, the average motorcycle can travel between 8.75 to 54 miles on reserve, depending on its fuel consumption and reserve capacity.
Main fuel tank vs reserve
In your user’s manual, you will find information that will inform you of the capacity of the main fuel tank and the reserve. However, it is important to know that both the main and the reserve gas tanks are sharing the same tank. They are not different tanks, and motorcycles do not have two different fuel tanks.
For example, if your user’s manual states that your fuel tank’s capacity is 6 gallons and the reserve is 0.9 gallons, it means that the reserve constitutes 0.9 gallons out of the 6 gallons. It does not mean the motorcycle has a capacity of 6.9 gallons because the reserve is considered part of the fuel tank.
The difference is that there are two feeder metal tubes in the fuel tank through which fuel flows from the tank to the engine.
One of the tubes is longer (about 3 inches off the bottom of the tank), and the other is shorter (about 0.5 inches off the bottom of the tank). The longer metal tube is the one associated with the main fuel tank.
When the fuel gets below it, you will be alerted that you are running low on fuel, and you have to switch to the reserve, which means you will close the long tube and open the shorter metal tube. The fuel that is found between the long and the short metal tubes is called reserve.
Can you increase how far a motorcycle can go on reserve?
The capacity of your reserve cannot be changed unless you modify the fuel tubes length. So you are limited with the fuel the reserve can hold.
This means that your best bet is to try and improve the gas mileage of your motorcycle. There are several ways you can do that. For example:
- Do not ride aggressively.
- Avoid traffic jams and routes that involve a lot of stopping.
- Improve the aerodynamics of the motorcycle.
- Use high-quality fuel.
- Do not overburden the motorcycle with too much weight.
- Making sure your motorcycle is kept in good working condition: properly inflated tires, using fuel additives, keeping the engine clean, etc.
Some motorcyclists prefer to bring extra fuel with them as they travel that they can use as a backup in case they run out of fuel. This can be achieved by using MSR bottles or other containers suitable for fuel storage or even auxiliary fuel tanks.
Oftentimes there will be a little extra fuel that may be left in the fuel tank (depending on its design and shape), so laying the motorcycle slightly on its left side and give it a good shake can slosh the fuel that can be left in the right side of the tank giving you few more miles.
Is it bad to run the motorcycle on reserve?
Running on reserve is not necessarily bad for the motorcycle. However, dirt, gunk, and other small debris can start accumulating over time on the bottom of the fuel tank, and running on reserve can lead to all that dirt being sucked through the feeder tubes. This could possibly clog up the fuel pipes, carb jets, or the filter.
You run on your main fuel tank until the low fuel light comes on, or the motorcycle starts to sputter. Then you switch to reserve and start looking for the closest gas station.
Usually, there is no need to worry while running on reserve. When you hit reserve, don’t ride too aggressively and make sure to stop at the next gas station and fuel up.
In most areas, there should not be too much distance between gas stations. Generally speaking, it is about 50 miles or so. However, in certain areas, there can be more distance between gas stations. If your next gas station is at more than 120 miles, this can spell trouble. Because of that, it is a good idea always to plan ahead.
This poses some dangers as one can easily forget how much fuel they have left in their tank (since the reserve is used as a low fuel remainder) And by the time the rider realizes the fuel is too low, it will be too late.
Usually, in this case, it is a good rule of thumb to keep a mental note of how far you can go with the amount of fuel you currently have in the tank and make sure to stop at a gas station before you run dry.
However, the danger in doing so is that you can easily overestimate how far you can go or underestimate how much fuel you are using. The motorcycle’s fuel consumption can change—sometimes quite drastically—depending on various factors, including your running speed and weather conditions. This could cause you to run out of fuel earlier than expected.
What happens if you run on reserve all the time?
Technically speaking, there are a few caveats here. However, nothing prevents a motorcycle from being run on reserve all the time.
See article: Can you run a motorcycle on reserve all the time?
There are usually a few different positions of the petcock.
- “ON” – This is the normal position in which the petcock should be. The fuel will flow normally from the tank to the engine, and fuel in the main tank will be used.
- “OFF” – This position of the petcock will prevent fuel from running to the engine.
- “PRI” – PRI stands for prime is the position that should be used for the initial filling up the carburetor after long-term storage or running out of fuel. Once the engine is running, the fuel petcock should be returned to the “ON” or “RES” positions.
- “RES” – This is the position of the petcock that allows fuel to flow normally from the reserve tank to the engine.
The rider can switch the fuel petcock to “RES” and run the motorcycle on reserve all the time. Doing so will not damage or break the motorcycle in any way.
This means the motorcycle technically runs on reserve and will severely affect how far it can go since it will include the fuel in both the main tank and the reserve.
With average fuel tank capacity between 2 to 7 gallons, this means that you can technically go as far as 420 miles on reserve.
So although you can say that the motorcycle can go more than a hundred miles on reserve, this will not be exactly correct. Up to 0.9 gallons of fuel will be the actual reserve, and the rest will be the main fuel tank.
The only problem is that you will not be alerted when the fuel in the main tank gets too low or reaches the reserve.