Are you looking for the best pit bike upgrades that will actually make a difference and be worth your money? Whether you just got your first pit bike or are looking to build your next custom pitbike, you’ve found the right article!
In this step-by-step guide, you’ll learn:
- How to know if it’s worth modifying a part on your pit bike
- Why some upgrades work better and others make your bike run worse
- How to choose the right mods and upgrades based on your specific needs & budget
What are the most popular pit bikes to modify?
There are many Chinese pit bikes that most of these mods will work on, but the most common pit bikes to modify are:
A pit bike is basically a small dirt bike with a horizontally-mounted engine with an open-cradle style frame – I just want to make sure that you’re reading an article that will actually work with your bike 🙂
Before you start modifying your pit bike…
It’s super exciting to modify and upgrade your pit bike to build it into a “New” feeling and handling dirt bike, but it’s also frustrating to spend a lot of money and time on mods and have it run WORSE than a stock bike.
I’ll go into more detail as I explain how each modification affects your pit bike, but I just want to caution you beforehand: you should know how each part (mod) will change how your pit bike runs or rides, and you should only make one change at a time.
Have you made this “upgrade” mistake?
A common mistake is making too many changes at once. That’s why it’s smart to write down your original settings (whatever part it may be), and then write down each change you make to test – that way you know exactly what each mod does – for better or for worse.
If you go the wrong way, such as a jetting or suspension change, you can always go back to your stock or original setting that you already know “works”.
One of the easiest ways to modify your pit bike is with a modified or aftermarket intake – but it’s also one of the easiest ways to ruin your engine.
You see, the intake is a very important part of your pit bike. It’s where the air is sucked in, and the more air you can shove into the engine, the more potential power you can make.
The problem with aftermarket pit bike intakes/pod filters
However, when you suck in more air, you’re more likely to suck in more dirt and mud – an engine’s worst enemy. Whether it’s opening up your airbox with more holes, or going to an aftermarket pod filter, it’s going to suck more dirt particles.
This isn’t a problem if you’re using a quality air filter, it’s properly installed and sealed, and you’re regularly cleaning or replacing the filter when it gets dirty.
Many pod filters are a dry mesh – this is NOT good for riding off-road. A mesh filter is made for flat track or drag racing where there’s little to no dirt.
What a good intake ACTUALLY looks like
The biggest problem with dirt bike intake setups is that they’re too short – according to this calculator, a good intake runner length should be in the 11-14 inch length range for optimum power.
But since that’s not practical, we have to stick with the stock air box, a velocity stack, or a lonely pod filter. The filter should also be properly oiled so that the dirt sticks to the foam and doesn’t get sucked into the engine.
So, if you want the best setup for more power that’s reliable, follow this guideline:
- Pod filter: Oiled foam filter (Amazon)
- Airbox intake: Large oiled foam filter (CRF on Amazon) with an open top (side holes drilled with foam pre-filters help keep dirt out)
- Pod filter for flat track racing: Mesh filter (Amazon) with or without velocity stack
The next big step is to get your carburetor jetted properly. If you do NOTHING else to your pit bike or dirt bike, do this one mod.
The difference between a poorly jetted carb and one that’s correctly jetted is:
- Easier starting – hot or cold
- Better and dependable throttle response
- More power at every RPM
- No bogging or hesitation
- Better fuel economy
- No spark plug fouling
If you don’t have this right, you’re going to be frustrated with how your pit bike starts and runs. This will also tell you if the pilot jet is too rich or too lean.
Carburetor jetting is only intimidating if you try to do everything at once. Just make one change at a time and write down what you did so that you can go back if your pit bike runs worse.
2 problems with “cheap carb upgrades”
A bigger carb can suck in more air at a higher RPM, but if the engine isn’t big enough, you’ll lose low-end torque.
Think of your engine as a vacuum… When you have a properly sized hose, it will have good sucking power, but if you take the attachment off/make the hole bigger, the sucking power is reduced – it needs a more powerful engine or more RPM to suck in more air.
The other issue is that the cheap “copycat” carburetors you see on Amazon are poor quality. While they may work, the tolerances are not good. This makes them harder to get properly jetted, and you may have to work on them at the beginning or more often to get your pit bike to run well.
How to know if you need a bigger carb on your pit bike
When you go to a larger carburetor, you’re going to lose power in the low-end/midrange unless you also make the engine and exhaust bigger to match.
So, if you don’t care about low-end torque, which makes your dirt bike easier to ride, then just replacing your stock carb is a good option if you just want more top-end horsepower.
But, if you want more power at every RPM, then the stock carb size is usually best unless you install a big bore kit with a better-flowing exhaust system.
Suspension – what can your pit bike handle?
Since most pit bikes or kids’ dirt bikes are made for riders that weigh less than 100 lbs, you’re going to have issues if you’re an adult. Unless you buy a quality pit bike with suspension already set up for an adult, you’re going to want to upgrade them.
Not only will the stock forks and shock bottom out easily (fully compress) and make it uncomfortable, but this can also be dangerous to you and your bike. Repeated abuse from bottoming the suspension can and will eventually break your pit bike.
Whether it’s the forks and shock that fail, or the frame welds crack, you want to be aware of what your pit bike can actually handle when it comes to your weight and how you ride it (trail riding vs jumping, for example)
Front forks: step-by-step upgrades
The front forks are just as important as the shock when it comes to a proper handling pit bike. Whether it’s too soft, too stiff, or not properly balanced, you’ll miss out on traction and a better handling dirtbike.
Here are the top pit bike upgrades for the front forks:
- Stiffer fork springs for your weight
- Heavier weight fork oil (Amazon)
- Adjusting compression & rebound damping clickers (if adjustable)
- Raising fork oil height
- Adding a preload spacer
- Adding air pressure
- Internal valving change (complicated & not always practical)
- Swapping/upgrading to a different front-end/fork & triple clamp assembly
Shock-ing facts (haha) for performance
The rear shock is extremely important on any dirt bike or pit bike if you care about traction and control. Getting the rear end height (ride height) is important so that the suspension is balanced front to rear.
For example, if the rear end is too low, your bike will be harder to turn and corner, and you’ll also have less front-end traction, making it easier to slide out the front wheel.
On the flip side, a rear end that’s too high will put too much weight on the front end, making it feel harsh and lacking stability at higher speeds or riding over obstacles.
Here are the best pit bike shock mods are:
- Adjusting shock preload to get proper sag/ride height
- Installing a heavy-duty shock spring for your weight
- Using heavier-weight shock fluid
- Increase nitrogen pressure (if applicable)
- Internal valving change (complicated & not always practical)
- Swapping/upgrading to a different rear shock
Skid plate – not just for riding over logs & rocks
While dirt bike skid plates are usually to protect the frame and engine when sliding over logs and rocks, pit bikes are more open to damage. Not only is the engine not protected by the frame, but the engine is essentially what’s holding the frame connected based on how it’s mounted.
So, adding a skid plate (Amazon) will protect your engine from hitting rocks and logs on the trails, but it will also make your pit bike chassis stronger.
Think about it – when you hit a big bump (and especially a jump), the suspension compresses and the frame flexes a little bit. Adding a skid plate brace will greatly reduce the amount of frame bending so that it’s much less likely to break the frame or engine mounts.
Gearing – the simple equation for speed
Changing the gearing won’t add any horsepower to your pit bike, but it’s one of the cheapest and easiest mods to make it quicker or faster – wait, what?
Yep, by changing one or both of the sprocket sizes (more or fewer teeth), you can make your pit bike accelerate quicker OR have a faster top speed. The compromise is choosing which you want more of.
For quicker acceleration, you want to either use a smaller front sprocket or a larger rear sprocket. This can help if you want a really low 1st or 2nd gear for trail riding or racing and you don’t care about top speed because it will be reduced.
For a faster max speed, you need to use a bigger front (countershaft) sprocket or a smaller rear sprocket on your pit bike. It won’t accelerate as quickly, but you’ll be able to cruise at a higher speed at a lower RPM and have a higher top speed, which is nice for riding on the road/gravel roads if your pit bike is street legal.
The stock bars on most pit bikes or kids bikes are weak and often too low if you’re an adult. It’s not only uncomfortable (cramped), but you might bend them with one simple tip-over.
Upgrading to a quality set of handlebars (Amazon) will make your pit bike feel bigger and you won’t need to replace them as often since they’re more durable. You can get a cheap set of replacement bars (Amazon) if you’re on a budget, but they likely won’t last as long (something to keep in mind when choosing).
Seat upgrade for your pit bike
While the stock seat may be just fine, upgrading to a taller seat foam (Amazon) can help give you more room. This is a helpful mod if you’re a tall rider or just have long legs that hit the handlebars easily while riding.
A taller seat makes your pit bike feel bigger because your butt is further away from the footpegs, giving you a more relaxed riding position if you’re sitting.
Exhaust upgrades for your pit bike
One of the first “go-to” mods for pit bikes is upgrading the exhaust, especially if your dirt bike has a quiet stock exhaust. But, you have to think – why are you “upgrading” the exhaust system, whether it’s the head pipe or the muffler/silencer?
The most common reasons why you’d want to mod/upgrade your pit bike exhaust are:
- Better sounding exhaust noise
- More exhaust noise
- More power/throttle response
- Better looks
- Less weight
How to know if an aftermarket exhaust is worth your money
Are your finances tight? If yes, then my honest opinion would be to save your hard-earned money and spend it on something more helpful – such as gas, tires, riding gear, or suspension improvements.
If you enjoy building pit bikes out and making them look nice or want to get a little bit more power, then it might be worth your money and time to swap your pit bike exhaust. A complete pipe and muffler system will typically give you the best results when it comes to torque and horsepower.
Cheap vs expensive pit bike exhaust upgrade
Do you have money burning a hole in your wallet? If you just want more noise then removing the stock baffle or buying the cheapest aftermarket pipe on Amazon might be your best option.
However, if you want a better running pit bike that has good overall performance, then it’s often worth spending a few more dollars – that doesn’t mean you need the most expensive exhaust.
A name-brand pipe and muffler generally have better quality when it comes to how it fits, durability, and performance when it comes to power and throttle response. I always read reviews for my specific dirt bike to get the best idea of what to expect.
Do you need to re-jet your pit bike carb with an aftermarket exhaust?
An easy mistake to make is not adjusting the jetting accordingly. Whether it’s because you’re intimidated by carburetors or you simply have no knowledge, you might have a poor running pit bike if you don’t properly adjust it after modifying your exhaust system (even if it’s just removing the stock baffle/end cap).
You see, when you change the exhaust, it changes how it flows from the engine – this changes the air-fuel ratio. It can make your pit bike run leaner or richer, both making your dirt bike start and run worse. It will also be harder to ride and not be as reliable.
Don’t worry, jetting isn’t as “mysterious” as you might think. I can show you how to get started in just a few minutes.
An engine upgrade is surprisingly easy on most pit bikes compared to an adult-size dirt bike – this is because the horizontal engine is out in the open and much easier to remove and install.
One of the easiest ways to get more power out of your pit bike is by upgrading the engine or installing a bigger engine – you can bolt a 150cc or 190cc engine onto most pit bikes these days.
If you’re going from 110 to 190 cc, that’s a 73% increase in engine displacement!
Installing a high-compression piston and/or cylinder head is a fairly simple way to make more power. Depending on how much compression you add, you may or may not need race fuel.
Increasing compression will typically give you a boost in low-end and midrange torque, which is nice for trail riding or if you’re a heavier dude that needs help in the acceleration department.
Do I need race gas with higher compression?
Generally, if you have an 11.0:1 compression ratio or lower, you should be fine to run it on premium pump gas (91 or 93 octane), assuming it’s properly jetted. However, if it’s detonating, you’ll either need to richen the jetting or use a higher octane fuel.
Examples of high-octane fuels are VP110 race gas or 100LL Avgas (aviation). You may be able to get away with running a mixture of pump gas and race gas, but it’s best to mix it only as needed – it will go bad and potentially seize your engine if it sits too long (speaking from experience, unfortunately).
Pit bike big bore kit – is it worth it?
Whether you’re considering an 88cc big bore kit (Amazon) for your CRF50 or a 143cc big bore kit (Amazon) for your KLX110, they’re a good way to increase power without replacing the entire engine. If you need to rebuild the top-end anyway on your pit bike, then a big bore kit is an easy way to increase performance without costing much more than stock parts.
A bigger camshaft by itself won’t make your stock pit bike much faster – in fact, it might make it slower. However, when you increase the engine size and compression, a bigger cam (KLX/DRZ on Amazon) is necessary if you want to make the most power.
When you have a larger engine that’s trying to suck in more air, a smaller (stock) camshaft is choking its potential because it will only the valves so much and so long. When you install a bigger (properly) sized cam, the valves will open more and longer so that the extra air and fuel can come in and out of the engine = more power.
Cylinder head porting
Another limiting point on your pit bike engine when you upgrade other parts is the intake and exhaust ports. They control how much air and fuel come in and go out of the engine.
Think back to my example of the vacuum with the smaller and larger hose – too big and you’ll lose flow velocity, but too small and it won’t flow enough air at higher RPMs.
That’s why it’s so important to buy or have your cylinder head ported by someone that knows what they’re doing. The goal is to make the most efficient ports – the smallest volume with the most flow.
Maybe you’ve seen bigger engine kits with the “Big Valve” heads. A bigger valve simply has the potential to flow more air and fuel into and out of the engine.
However, going too big will decrease velocity, and low speeds = loss of low-end torque. I wouldn’t recommend larger valves unless you’re building a high-output pit bike race motor.
Inner rotor kit
A flywheel is a heavy weight used to smooth out the power curve to make your dirt bike easier to control when accelerating or decelerating, but what happens when you remove most of that extra weight?
It revs quicker, which gives you a snappy throttle response and quicker acceleration. This is a fairly simple mod when you install an inner rotor kit (Amazon) on your pit bike.
The problem with inner rotor kits
Besides quality issues that can make your pit bike hard to start or have a weak spark, the main drawback to less flywheel weight with a lightweight inner rotor kit is that the power is less controllable.
This is more of an issue if you’re a beginner or just want a smooth throttle response. With less weight, not only will your pit bike engine rev quicker, but it will also decelerate quicker when you let off the gas (engine braking).
3 issues with installing a bigger pit bike engine/motor
While a bigger engine can be the best mod for your money, you might be limiting its potential by making 3 common mistakes. All of these problems can be resolved, but they require more time and money.
First, when you make your pit bike faster, you’re more likely to ride faster and/or jump higher.
This means that the suspension and chassis will take more of a beating. If you add more power without upgrading the suspension (and possibly the frame), you’re going to have an uncomfortable ride that could lead to a bad crash because it’s too soft.
Second, a bigger engine sucks in more air – this means you need more fuel to match the mixture. Whether it’s adjusting the jetting or upgrading the carburetor, it’s important to plan ahead.
Third, the exhaust is also going to be a limiting factor. A stock exhaust system is made for the stock engine size.
That means the engine is going to be pushing out more exhaust gases than the pipe and muffler can efficiently flow. A bigger (properly-sized) exhaust system will give you the most power at every RPM in your power curve.
The best pit bike upgrades – putting it all together
Continuing on from the 3 issues above, you need to plan your mods ahead of time if you care about performance. In other words, you have to choose the right mods for a certain type of power curve, whether it’s for all-out horsepower for racing or better overall power for trail riding.
Below are examples of the best mods based on your specific needs:
Best pit bike mods for racing
If you just want maximum horsepower for racing and don’t need low-end torque, then you want the best flow for high RPM. This is not a practical setup, nor is it easily controllable because it requires a lot more clutch work and more experience/stamina to keep your pit bike at a high RPM while riding/racing.
These are the best pit bike mods for racing at high RPM only:
- Biggest carburetor – properly jetted
- Biggest engine option
- Larger intake & exhaust ports and valves
- Bigger camshaft with high lift & duration
- Best flowing exhaust for high RPM
- Lightened flywheel/inner rotor kit
Best pit bike mods for trail riding & overall power
If you prefer a more practical setup that’s easy to ride and makes more power from idle on up to redline (my personal preference), then you’ll want to combine the right size and type of parts for an efficient running engine.
These are the best pit bike mods for trail riding & overall power increase:
- Stock or slightly larger carb – properly jetted
- Higher compression and/or larger engine
- Stock or recommended size ports & valves for maximum low-speed velocity
- Bigger camshaft to match engine size and compression (more lift with not as much duration, generally)
- Better flowing exhaust matched to engine and carb size (a properly stepped diameter head pipe often works best)
- Stock flywheel
The complete list of pit bike mods that make a difference
These are the top 17 pit bike mods & performance parts to make your bike faster & safer:
- Carb upgrade
- Fork upgrade
- Shock upgrade
- Skid plate reinforcement
- Gearing change
- Exhaust mod/upgrade
- Increase compression
- Big bore kit
- Larger valve(s)
- Inner rotor kit
- Install a bigger engine
The best mod to make you a faster AND safer rider
All of these pit bike mods can make your bike faster and more comfortable, but there’s one modification that TRUMPS them all… It’s a modified rider (YOU), and I want to show you how to do that so you will ride faster and safer on any dirt bike – click here to get my FREE basic techniques guide.