I am sure you know that bigger engines need bigger carbs – but what happens if you upgrade your carb to a bigger one? Without changing anything else, will you get more horsepower?
Bigger carburetor alone will not give you any horsepower. But instead, if you also install bigger carburetor jets and a performance exhaust system, you could gain up to 15-20 horsepower. That’s a significant improvement for motorcycles.
If you are confused by this, don’t worry. I will talk in detail about carburetors, carburetor jets and what you really need to get horsepower. It’s not as simple as switching to a bigger carb but I promise it’s also not that complicated!
How Does A Bigger Carb Give More Horsepower?
A bigger carburetor has a bigger space that can help to increase horsepower by allowing more air and fuel to travel into the combustion chamber at once.
More air and fuel in the combustion chamber means bigger combustion is generated. Thus, more horsepower.
Actually, a bigger carburetor alone will not increase horsepower. Just because you have a bigger space for air and fuel to travel, doesn’t mean you will actually have more air and fuel.
A bigger carburetor is just one component in the horsepower recipe book. To correctly increase horsepower, you need all of these components:
- More air – Can be provided with performance exhaust system or air filter
- More fuel – Can be provided with bigger carburetor jets
- More space – Can be provided with bigger carburetor
I will come back to this horsepower topic later. But for now, let’s clear some misconceptions – Carburetor Vs Carburetor Jets.
Difference Between Carburetor Vs. Carburetor Jets
More often than not, beginner enthusiasts confuse carburetors with the carburetor jets – they think it’s the same thing but really, it’s not.
When I mention carburetor size, I am referring to the size of the carburetor body. Bigger carburetor body means more air and fuel can pass through and enter the combustion chamber for bigger combustion.
Bigger carburetor size means bigger body for air and fuel to flow through.
On the other hand, carburetor jets are components inside a carburetor that control the amount of fuel that can enter the carburetor body.
To actually have more horsepower, you need to increase the amount of air and fuel. Which means, it’s important to also enlarge your carburetor jets – and not just the carburetor body.
Thankfully, if you purchase a new and bigger carburetor, it should come with bigger jets as well. It was just important to clear this misconception first in case you had it.
Carburetor jets in different sizes
How To Correctly Increase Horsepower With Bigger Carburetor
Earlier I told you that to correctly increase horsepower, you need 3 components:
- More air
- More fuel
- More space
I want to talk about each of them in detail and the best way to acquire them. This ensures you are correctly adding components that will result in extra horsepower.
1. Getting More Air For Horsepower
During a combustion cycle, air always enters from an air intake, gets converted into exhaust gases and escapes outside through the exhaust pipes. This is why there are two primary methods to increase the amount of air for horsepower.
Method #1 – Get more air using a performance air filter. Air filter’s job is to filter out any impurities in the air before they enter your engine and are used for combustion. Stock air filters are very good at filtering dirt but they also make it hard for air to enter.
Swapping your air filter into a less restrictive one is a great way to get more air. I suggest you look into pod air filters for this. Here’s another article I have about it – Are Pod Air Filters Worth It?
Pod air filters allow more air to enter
Method #2 – Get more air using a performance exhaust system. An exhaust system’s job is to remove the exhaust gases generated in the combustion chamber as quickly as possible.
The quicker exhaust gases are expelled out, the more room is available in the combustion chamber for air to enter.
Without getting into too much detail, a performance exhaust system can remove exhaust gases from the combustion chamber much quicker. This way, there’s always more room for air to enter the combustion and be utilized to generate horsepower.
Here’s more details on motorcycle exhaust systems if you are interested – How Much Horsepower Does Exhaust Add To Motorcycle?
Motorcycle full system exhaust improves exhaust flow significantly.
These methods to get more air for horsepower are not either or. Performance air filters are the cheaper option but an exhaust system has much more benefits. If you have the budget it’s possible to replace both with aftermarket versions.
2. Getting More Fuel For Horsepower
During a combustion cycle, fuel is always injected from the bike’s fuel tank. Modern bikes use a fuel injector system, while old school bikes use a carburetor (I assume your bike also uses a carburetor)
To increase fuel injection from a carburetor engine, you need to install bigger carburetor jets – not an entirely bigger carburetor, just the carburetor jets.
Bigger carburetor jets allow more fuel to enter the carburetor from the fuel tank. Usually, installing bigger jets alone is enough.
Installing a bigger carburetor altogether is only done for major modifications, where you have significantly improved your bike’s air intake and fuel injection.
3. Getting More Space For Horsepower
Usually, a stock carburetor has enough space to handle more air and fuel than normal.
Which means, once you install a performance exhaust and replace your carburetor jets, you could already expect horsepower gains – without having to replace the carburetor.
Carburetor space is only a problem if your air intake and fuel injection have been upgraded significantly – to the point where the carburetor does not have enough space and becomes the bottleneck.
This is unlikely to happen. Unless, you also upgrade the main engine – stuff that no beginners should be attempting.
That being said, upgrading a carburetor into a larger one ensures that more air and fuel can travel through and result in more horsepower.
For the last time, you should only consider getting a bigger carburetor once you have upgraded your exhaust, air filter and tried carburetor rejetting.
Getting a carburetor that’s too large is bad for your motorcycle. More info in this article. Will Bigger Carburetor Make Bike Faster?
Bigger Carb Vs Smaller Carb
So far we have been focused solely on larger carburetors. But is a larger carburetor always better?
Actually no. A bigger carburetor has enough room for more horsepower and is usually equipped with bigger engines.
This means a bigger carburetor gives you power at the high RPM range. Whereas a smaller carburetor gives you a more responsive throttle. Your bike will feel aggressive and shifty at the lower RPM ranges.
Depending on your use cases, a bigger carb is not always the best option. If you are into tracking or cruising, then a bigger carb (more power at high RPM) is optimal.
If you are into off-roading in dirt bikes, then a smaller carb (more power at low RPM) is better.
