In this guide, I’ll show you why you would even want to modify your “little girls” trail bike, all the best mods based on your budget, and how to get the best overall performance by combining specific parts.
Is it worth modifying your CRF250F trail bike?
Well, if you’re like me and many other people, you like a slightly smaller and simpler bike, but you also enjoy tinkering and modifying things to make them better.
The CRF250F is a pretty good trail bike, but not if you’re a more experienced rider due to lack of suspension and power. With the right mods, you can turn it into a ‘sleeper’ woods weapon that will have guys on 300’s and 450’s turning and scratching their heads, wondering what just passed them on the trail.
Will it be the fastest bike or be able to do well on the motocross track? No, but it’s simple, reliable, easy to ride, and just plain fun to ride a “slow bike” fast.
How much horsepower does a Honda CRF250F have?
To start, a CRF250F only has about 20 HP, but peak horsepower means very little in the off-road world. Why? Because you rarely hold the throttle wide open other than the occasional straightaway – you’re mainly going to be in the midrange of the RPM.
Having a good, broad torque curve makes it easy to ride off-road because you don’t have to keep it revved up at a narrow RPM range.
The CRF 250F makes good torque from idle all the way to about 8k RPM – this means you can lug it and short-shift and still be able to accelerate at a low RPM.
Suspension – Is it worth upgrading?
Before you do any engine or power mods, you need to give the suspension some attention because it’s the biggest safety factor. The stock suspension on the CRF250F is soft and the valving is poor, but what does this mean?
Well, if you’re a heavier rider or you just want to ride more aggressively at a faster pace than a novice rider, then you’re going to start getting bucked around. The stock forks and shock will bottom out and the compression and rebound won’t be able to keep up if the terrain is rough.
This will be uncomfortable and eventually dangerous because the tires won’t stay planted on the ground and you’ll lose control more easily.
The first step to suspension upgrading
Before you start trying to swap forks and a shock over from the latest CRF250R motocross bike, you need to ask yourself a couple of questions.
What’s your goal and what’s your budget? If you just need a little better working suspension for the cheapest amount, then stick with the stock front forks and rear shock.
Want to invest more time and money into a conversion project because you’ll be riding this bike for many years? Then a bigger upgrade might be best for you.
The only problem is that the CRF250F is a newer model, so there haven’t been as many mods or conversions done yet, unlike the popular CRF230F.
The stock forks are pretty good if you’re a beginner rider that’s under 180 pounds because they’re soft. They give you a comfortable ride on the trails and soak up a lot of the little bumps at low speeds.
The problem is they blow through the stroke too quickly if you’re riding aggressively or are a heavier rider.
Cheap fork upgrade
If you just need to make them stiffer or hold up better and you’re on a budget, then you need to start with heavy duty springs. Stiffer fork springs alone can help a lot – if it’s too stiff then you can try 1 stiff spring and 1 stock spring in the fork legs.
However, it may still feel like a pogo-stick. You can also try heavier weight fork oil (Motosport) and increasing the oil height (reducing the air gap).
Both of these slow down the compression and rebound damping and help resist bottoming.
Somewhat cheap DIY fork upgrade
Race Tech has gold valve fork emulators that can be added to the stock forks for better performance. If you don’t mind taking apart the forks and doing some simple testing, this might be a good option for you.
It’s essentially a damping adjustment, but it’s internal, which is the biggest drawback. Your stock forks can work quite a bit better, but you have to be willing to install them at least once to find a comfortable setting.
Expensive fork upgrades
With limited technology, there’s only so much you can do with the stock forks. That’s why fork or front end conversions are popular among hardcore trail bike owners.
Unfortunately, the CRF250F is so new that I have yet to see someone do a fork swap fr another bike, so I can’t tell you all of the required components.
With that said, the XR400 forks are popular on the CRF230F and XR250 as an upgrade, so maybe someone will figure out an easy way to swap them on the CRF250F – it’s probably a simple mod on the triple clamps to fit.
Stock Shock woes
The rear shock is probably the weakest link because it can be dangerous and is harder to adjust or replace. It’s fine if you’re a beginner or casual rider, but once you start riding faster on rougher terrain, you’ll start getting bucked around.
This is because the rebound damping is too slow. So, if you hit two consecutive large bumps, the shock will compress and won’t have enough time to fully rebound.
When you hit the second bump it will compress even more and then when it rebounds it can throw you forward unexpectedly. A stiffer spring (Amazon) will help if you’re a heavier rider, but it won’t completely fix the problem if you’re an aggressive rider.
Rear shock upgrade
If you’re extremely mechanically inclined, you can take apart the stock shock and opening up the valving to make it flow more. It’s a lot of work, and it won’t get huge gains. You still won’t have any external adjustability other than the sag/ride height.
For a much more expensive upgrade, you can send your shock to Race tech, as Rick Ramsey did with his CRF250F. It’s much better than stock, but there’s still no damping adjustment externally.
The stock intake is sealed up very well to protect the airbox and air filter from water entering. This also chokes it from getting enough air when you want to get the most power.
You can cut out a section on the top of the air box to allow more air in. This will certainly help when you add an exhaust and get a fuel tuner.
The stock exhaust is pretty good on the CRF250F, and it’s definitely quiet, making it a good choice if noise is a concern. It also has a USFS approved spark arrestor so you can legally ride on state trails.
The downside is that it’s heavy and it restricts some power. You can remove the baffle to open it up a little bit.
Just remove the end cap and take off the baffle. You should get a little better throttle response, but it will definitely be louder.
What you need to know about an exhaust upgrade
One of the easiest ways to bolt on more power is with a complete exhaust system – the head pipe and muffler. A properly tuned exhaust will flow better at a specific RPM range to get the most power.
When I say “specific RPM range”, I mean that most pipes add or move power to a certain RPM range. For example, an aftermarket exhaust for the CRF250F will most likely give you more horsepower in the midrange and top-end because that’s where the stock system holds it back.
Do I need to tune it with an exhaust change?
With that said, you need to use a fuel tuner to adjust the fuel mixture if you want the best (or just better) results. You might actually lose some performance and reliability if you just swap the exhaust and do nothing else.
An aftermarket exhaust will flow better and the fuel injection system can’t tell anything changed, so it’s going to run leaner and hotter. This can lose power, cause the head pipe to get red hot, make it hard to start when cold, and cause backfiring.
FMF powercore 4 slip-on
The slip-on is just the muffler, which is very easy to install. It works with the stock or an FMF head pipe.
With the powercore 4 (FMF), you get a better sound, better looks, less weight, a little more horsepower, and more noise. With just the muffler, it’s the easiest and also the cheapest option, but provides the least amount of performance gains.
This is because of the smaller inlet diameter. It restricts exhaust flow because it matches the stock head pipe size.
It also comes with a removable spark arrestor screen (Motosport), allowing you to ride on trails legally.
Pro circuit T4
For a complete exhaust system from head pipe to muffler, the PC T-4 (Pro Circuit) is the next best affordable upgrade. You’ll get more power, better sound, less weight, and a much better look.
Pro circuit is generally one of the louder options, especially if there’s a screen or quiet insert that’s removed. The T4 has a removable USFS approved spark arrestor screen for trail riding.
The Yoshimura RS2 (Motosport) is comparable in price to the PC exhaust – you get basically the same features, but they actually post a Dyno chart compared to a stock exhaust.
With the Yosh full system you get more torque and horsepower at virtually every RPM when properly tuned. The biggest gains are mid to top-end power.
Which exhaust is best?
- Cheapest with better sound and look: FMF Powercore 4 slip-on
- Best Bang for buck complete system: Yoshimura RS2 (Motosport)
Whether you modified the intake or exhaust, or just want your Honda CRF250F to run the best, you’ll want a fuel tuner. A fuel tuner is basically an all-in-one jet kit in a handheld electronic device.
Why you might need a fuel tuner
While the stock fuel injection system is supposed to compensate the air fuel mixture so that your 4 stroke dirt bike always runs well, it’s still very limited. It only compensates for certain variables, such as air temperature, air density and humidity, but not other important things.
For example, you can ride in the morning at 4000 ft elevation when it’s 50 degrees, and then ride at 9000 ft elevation when it’s 77 degrees and your bike will run well. But, when you change out the exhaust or modify the intake, it will most likely run poorly compared to stock.
This is because the fuel injection system does not adjust based on the EGT (exhaust gas temp) or how much air is going through the intake. So, this is why you need a fuel tuner if you want your modified CRF250F to run well as stay reliable.
Not getting it tuned with an aftermarket exhaust can cause it to:
The EJK tuner is simple and plug-and-play. There’s no complalicated tuning involved.
It has pre-programmed maps, so all you have to do is pick one and go ride to see which one you like. You might have to try a few different ones, but it’s pretty quick to plug in and change – no laptop/computer required.
If you want the most in custom tunability, the Dynojet power commander is your best option. As a result, it’s more expensive, but you can tune just about everything when it comes to power, reliability, fuel mileage, and overall control and performance.
It comes with pre-programmed maps, but you can also tune based on RPM, throttle position, and more. You can also get a map switch for your handlebars to alternate between maps on-the-fly.
You’ll need a Micro USB cable and USB to Micro USB adapter (sold separately). It also only works with a windows PC.
Do you want more acceleration or more top speed? Changing the gearing won’t affect horsepower, but it can make a big difference in how your CRF250F rides.
Changing one or both sprockets can give you an ultra low first gear that’s already low for tight and technical trails. Or you can space the gears out more and get a higher top speed for more comfortable crushing.
Want better acceleration? Use a smaller front sprocket and/or a bigger rear sprocket (Motosport).
Want more top speed? Use a bigger front sprocket and/or a smaller rear sprocket (Motosport).
Getting tires for the terrain you’re riding will be the most helpful. This means that if you ride in rocky or hard-pack soil, you’ll want hard-terrain tires that have a softer rubber compound to get the best traction.
Getting the right front tire is very important if you want frontend traction, feel and confidence so that it doesn’t slide out when you least expect it.
Unfortunately, there’s no “best tire” because it depends on where you ride, how your bike is setup, and what you like to feel under you – your riding technique makes a big difference to the balance of your bike.
With that said, these are some of the best tires I can recommend for the Honda CRF250F:
How to make maintenance easier
While not necessarily a mod, it’s nice to know how many hours your dirt bike has on it for a number of reasons. You know when to do preventative maintenance, or how much longer you can ride before needing a suspension or engine service.
A simple hour meter with a tach (Amazon) is one of the cheapest mods, but it will save you time and money in the long run from ‘guessing’ how long ago your last oil change was…
Lowering a CRF250F
Maybe you’re a short rider like me and want a full size dirt bike but the seat height is just a little too tall. One of the easiest ways to lower your CRF250F without making it a permanent change is with a lowering link.
The Kouba Link (Amazon) is pretty easy to install and instantly lowers the seat height almost 2 full inches, give you more confidence as you can touch the ground easier. It does affect the handling – it will feel more stable and steer slower, but if you’re a beginner you probably won’t notice it.
You can also get it at Motosport – Check price now.
After you build your confidence and are ready to go back to the stock seat height, just bolt the stock shock linkage back on.
Lightweight lithium battery
Did you stock battery die or is it getting too weak to reliably start your CRF 250F? Upgrading to a more powerful battery will help, but going to a lightweight lithium battery (Motosport) will also shed some easy pounds off.
Most lithium batteries are 2-3 pounds lighter than a stock lead acid battery. The only downsides are that they can get weak when cold (below 40F) or if they don’t get used often.
- Tap the starter button once
- Wait 1 minute
- Tap the starter button again
- Wait one minute
- Now trying starting your bike (with choke on)
The stock seat is pretty hard and uncomfortable if you ride long long days and sit down a lot. A seat concepts seat is a nice upgrade because is wider and forms to your backside better so you don’t have a sore and aching rump the next day!
Skid plate – what kind?
Do you ride trails with lots of logs or rocks? An aftermarket skid plate will help protect the underside of your frame and engine from those hard hits.
Stronger & more durable
An aluminum one can affect the handling characteristics because it’s so stiff and solid mounted to your frame. It can also create more noise fr vibration.
With that said, an aluminum skid plate is best if you plan on banging off of it all the time because it’s much more durable than plastic or carbon fiber.
Lightweight and functional
An upgraded plastic skid plate is really nice because it covers most or all of the essential parts underneath and it’s very lightweight – almost as light as an expensive carbon fiber skid plate. It’s also queit and fairly durable as long as you aren’t constantly hitting big rocks with it.
Depending on the build quality, you might have to manually notch the bolt holes to make it fit well, but that’s usually a minor job.
Oversize gas tank options?
The CRF250F already gets pretty good gas mileage, but am oversize gas tank will allow you to ride even longer without needing to fill up. Unfortunately, I still haven’t sourced an aftermarket gas tank for the CRF 250F trail bike, which is disappointing, because the stock tank only holds 1.6 gallons.
So, for now, your best choice is an auxiliary gas tank (Motosport). You can mount it to a rear rack or your rear fender. It’s less exhausting than carrying the fuel in a backpack…
Bigger gas tank disadvantages
If you do find an oversize gas tank for the Honda 250F trail bike, fitment could be an issue. A quality aftermarket fuel tank should fit without any problems if your dirt bike is completely stock.
But, if you have a different front end or other aftermarket parts that could get in the way of a bigger tank, just be aware that it might need some mods to fit and function properly.
Big bore kit
There are some big bore kits available, but I haven’t seen any in the United States yet. The CRF250F is popular in other countries, such as Brazil.
There’s a 286cc and 310cc big bore kit, but it might be hard or impossible to get it shipped to your country. There should be some more big bore parts and hotter camshafts sometime soon, but it’s still a fairly new model.
Dual Sport Kit
Whether you want to turn your CRF 250F into a street legal dirt bike or just want a lightning kit to ride at night, there are plenty of options. But that’s also a problem – where do you start?
To make it simple, you need a:
- Tail light
- Turn signals
- Handlebar switch & wiring harness
You can never have “too much headlight” when it comes to brightness on your dirt bike, especially if you’re riding at night. A quality set up is a Baja Designs LED
Or if you want to skip the wiring and tail light, you can get a Polisport Solar Headight (Amazon). It runs off of a battery that charges during daylight, so you don’t need to worry about your stator capacity and having to re-wind it for more juice.
The Lookos Solar Headlight will give you around 2 hours of light in “High” mode, and about 4 hours on “Low”. It’s best if you’re commuting short trips in the dark or need it in case of emergency if you get stuck out on the trail at night.
Phone mount holder
It’s really nice to have a GPS mounted to your handlebars for dual sport or long Enduro rides, but what if you want to use your phone? Having it stored in your riding jacket or pants might be accessible when you come to a stop, but it’s not the most convenient.
That’s why a handlebar phone mount is super nice, but you don’t want just any mount to hold your $1200 cellular phone device. A Ram mount phone holder (Amazon) will get the job done well because it’s well made and super sturdy. My Ram mount hasn’t moved since I mounted it several years ago!
The best mod to make you faster & safer
All of these mods can make your bike faster and potentially safer, but there is one mod that beats them all, and you can use it on any dirt bike you ever ride!
The best mod is a better rider, and I want to show you how to do it faster by learning the basic techniques that most people don’t master. Click or tap here to grab your Free basic techniques guide now!