13 Best CRF230F Mods – Is It Worth Modifying A Girls Bike?

Are you looking to upgrade your Honda CRF230F? There’s many parts you can add to make it faster. This is the ultimate list of CRF230 mods that actually improve its performance. 

Are you ready to turn your “Little girl’s bike” into a “sleeper bike” that will make guys on bigger bikes look twice when pass them on the trails? I must warn you, though… The more mods you do, the more addicting it gets. And the more giggles you will have under your helmet when riding this “Little Red Pig”. 

Having fun in the woods on my CRF230F

Performance Mods Part 1

This will be a 2 part series, just like when I covered the list of XR200 mods. Part 1 will be all about performance modifications that will make your CRF230 faster or make it easier to ride, which in turn will make you faster because you are more comfortable on it.

Some of these mods are free or cheap for how much of a difference they make. The CRF230F will never be the best motocross bike, but there’s a lot of potential hiding underneath. If you enjoy trail riding in the woods, mountains, or any kind of single-track, then you’re in for a surprise…

Here is the list of the 13 best CRF230 mods:

  • Airbox
  • Air filter
  • Rejet
  • Muffler
  • Rear shock
  • Forks
  • Tires
  • CDI Upgrade
  • Exhaust
  • Carb
  • Big bore kit
  • Camshaft
  • Porting
  • Flywheel key
  • Lightened flywheel
  • Adjustable camshaft sprocket

Is The CRF230F Power-Up Jet Kit Worth It?

Honda builds their off-road trail bikes to meet EPA and emission standards in certain countries. This means that they will run too lean in most climates. The CRF230 definitely needs to be re-jetted to get the most performance out of it. This includes both stock or modified 230F’s. 

Many 230 owners may realize this and do a quick search to find that there is a “CRF230 Power Up Jet Kit“. This kit includes a new special needle, a couple different main jet sizes, and a new pilot jet. The cost is about $50, which is reasonable for an upgrade that makes a noticeable difference.

DIY & Save A Few Bucks

If you like tinkering on your bike with mods, then there’s a cheaper way to get the same amount of performance as the Power Up Jet Kit. Instead, you can buy individual main and pilot jets in addition to a stock 2003-2005 CRF230F needle. 

Stock Honda CRF230F Jetting Specs

The stock jetting on a CRF230F is lean for most climates, which is why the Power Up Jet kit is available. The stock pilot jet is a 42 and the main jet is a 110. Going up to a 45 pilot and a 120 main will gain power and throttle response in most cases. 

The 2003-2005 CRF230 comes with an adjustable needle. Going from the middle clip position to the 4th position from the top should also make an improvement. 

Why Different Main Jets?

The power up jet kit needle has a different taper, so it requires a richer main jet than if you run the stock 03-05 needle. If you have the power up needle then it will run better with a 132-135 main jet if your bike is stock for average climates. A 120 main will run better with the stock 03-05 CRF230F needle.

How To Un-Cork Your CRF230F

A lot of trail bikes come corked or choked up from the factory. Usually for emission and sound limit reasons to meet EPA requirements. Changing the jets in the carb, as you just read, was part of the un-corking process.

The CRF230 has a baffle/restrictor on the intake and exhaust. These do help keep the sound output down, but they’re limiting some potential power. 

To un-cork a Honda CRF230F, simply remove the intake air box lid and exhaust baffle. Jetting must be changed if it’s still stock from the factory. 

Air Box

The CRF230 has an average-sized air box, but there’s not much room for air to get in to reach the carb. The more air you can get through the carb, the more potential gas you can get through it as well, which will make more power. This is theoretical, of course, because the engine has to be able to properly burn all of that air and fuel to make the power.

Why do we install bigger carbs on dirt bikes? They suck more air in to boost the horsepower (when properly tuned). However, other factors come in to play, such as the velocity of the air. Air velocity is how fast the air is going through the intake, which plays a bigger role in low-end torque.

For example, when you go to a bigger carb the top-end power is increased, but some low-end torque is usually lost. To get into the science of it is interesting, but that’s not what this article is about.

Remove The Lid

There is a lid on the top of the airbox that can be removed to make the opening bigger. You’ll need to take the seat off to access it. 

A little more dust will be able to get in, but it’s generally worth it if you’re looking for more power. This is why it’s important to have a quality air filter that is regularly cleaned or changed. 

Air Filter

Going to a quality aftermarket air filter will also allow more air through, giving you more power and better throttle response. Just remember to keep it clean, especially if you ride in sandy/dusty areas. 

Muffler Baffle/End Cap

While the stock head pipe is the biggest restriction (more on this later), the factory muffler on the Honda 230 has a baffle with a built-in spark arrestor on it. This can be removed to gain some low-end torque and throttle response. 

However, this will greatly increase the sound decibel output. I don’t recommend this modification if you live in a suburban area with neighbors close by or if you ride at a trail/park that requires a USFS approved spark arrestor

Riding up a mountain on my Honda CRF230F

Suspension

The last part of a trail bike that gets a technology update is usually the suspension. This is because affordable trail bikes are built for a beginner rider or someone that doesn’t have enough experience to tell a difference between good and bad suspension. 

The CRF230F suspension is 1970s technology, but that’s okay. It’s super simple, easy to work on, and reliable. The problem is that once you start riding at higher speeds over rough terrain, the stock forks and shock will beat you up and may even throw you off the bike.

What’s Your Budget & Timeframe?

There’s several options available for modifying or upgrading your CRF230 suspension, but the best options are hundreds of dollars. If you plan on keeping this bike for years to come, it may be worth your time, effort, and investment. 

Rear Shock

The rear shock is the most troublesome part on the CRF230 when it comes to performance. Honda continues to ignore this subpar, yet vital suspension component that can cause safety issues if you are an aggressive rider.

Stock Shock Woes

The stock shock on the 230 actually has a good spring rate for a medium sized beginner trail rider. The problem is the internal valving that can and will give you a hard time over rough terrain when you push the pace hard enough. 

The rebound damping is too slow. This is a problem when you have two consecutive bumps or obstacles that will compress the rear shock in a short amount of time.

The first bump will compress the shock, but the shock rebounds too slow. By the time you hit the second bump the shock is still trying to rebound. This will compress it even more than the first bump did. After that is when it will try to buck you off because it now can fully rebound, but it has a lot more built up force from compressing twice. 

Stock Shock Re-Valve

The stock shock can be re-valved by a professional, such as Bruce Triplett, but even he says that the stock CRF230F shock is limited. It’s the most affordable shock upgrade and will definitely make a difference, even if you’re an average rider with little experience.

Depending on who you send it to, it’ll be around 200 bucks. That’s not very expensive for a re-valve, but you’re missing out on any external adjustments for better performance, aside from the spring pre-load. 

Hagon Shock

A Hagon rear shock is a complete aftermarket shock for the 230F. It’s a big improvement over the stock shock, but it’s still limited due to lack of adjustability. It has a compression/rebound clicker adjustment, and the pre-load can be adjusted. There’s no remote reservoir or high speed damping.

Works/Other Shocks

There’s other aftermarket shocks that seem to come and go as far as resale and availability. The best shocks for a CRF230F generally have a remote reservoir with complete compression and rebound damping adjustment, as well as high speed compression damping. 

High speed damping control is great for trail bikes because it can make a choppy ride feel plush without bottoming out easily. High speed compression damping controls the compression speed when you hit obstacles that compress the suspension at a high rate of speed. This would include small bumps, rocks, roots, etc. Being able to soften it up for the small stuff without effecting the suspension on bigger hits will make your ride softer so you’ll be able to ride longer.

Forks

The stock CRF230F forks are adequate for a new rider, but they are very soft and one-dimensional. They only have about 9.5″ of travel, so this is one of the biggest disadvantages compared to other full size trail bikes with 11-12 inches of suspension travel. 

The stock 230 forks can be modified. Heavy duty springs are a common mod, but that only makes them a stiffer one-dimensional set of forks. When I say one-dimensional, I mean that the rate at which the forks compress is the same throughout the entire stroke. This is due to there only being one hole on each damper rod for the fork oil to flow through. This is referred to as suspension damping. 

Stock Fork Mods

I like to work on and modify my own bikes and parts, but when it comes to suspension work that I’ve never done before, I consider sending it to someone and see what they did and how it works. In the case of my CRF230, I sent my stock fork damper rods and springs to Bruce Triplett because he knows his stuff when it comes to older style RSU (right-side-up) forks. The 230 community regard him as the guru for the stock suspension components and how to set them up for each person’s weight and riding ability. 

Modded 2005 Honda CRF230F
CRF230F with Bruce Triplett modified forks.

For about 110 bucks I got them back and installed them myself. I was greatly impressed because the damping was much more progressive, and the pre-load was spot on for my weight. For the best budget fork upgrade, a good tuner like Bruce is the way to go, especially if you’re intimidated by working on suspension. He is extremely easy to talk to and will explain everything in detail. His speed and cost are beyond fair in my opinion.

Fork Conversions

There are numerous fork conversions that have been done to the CRF230F. Whichever kind of fork setup you want depends on how much work you’re willing to do. 

CR85 Fork Conversion

Probably the first and most popular fork swap was the CR80/CR85 forks, which is what I have on my 230. They are one of the lightest forks that can be fitted to this bike. Adapter kits were being made by at least one manufacturer/person, but they can be difficult to source if you don’t have the resources to make your own adapter parts.

The CR85 forks require a lower triple clamp relief mod for the steering stem to be long enough, wheel spacers, brake caliper adapters, fender mounting mods, and a longer brake line. There’s probably a couple other small things to make everything fit and work. 

CRF230F CR85 Fork Conversion
CRF230F with CR85 forks.

Then there’s setting up the fork spring rate and valving. Stiffer springs are required, but the valving needs to be softer for trail riding or else it will be a harsh ride. If properly set up, these forks are on another level compared to the stock 230F forks. Having extra travel helps too. 

XR400 Fork Swap

The latest popular fork conversion is taking a complete XR400 front-end and bolting it onto the CRF230 chassis. There are still some small mods that need to be done, such as shortening the steering stem, but these are very capable forks, especially after some valving changes. 

Tires

Do you have the original tires on your CRF230? Even if they still have plenty of tread left, going to a different tire for the appropriate terrain will be an upgrade. After suspension, tires are the biggest factor to riding comfortably and confident, which will accelerate your skill and speed. I really like the Shinko F546 on the front and a IRC VE33 on the rear. They both work well in every terrain I’ve ridden my 230F.

Upgraded CDI Box

The CDI (ignition box) controls the timing of the spark that produces combustion for the engine. The stock CRF230F CDI is very mellow, to put it plainly. It’s a lazy ignition curve so that the power-curve is smooth, soft, and it won’t cause any pre-ignition problems.

An aftermarket ignition will advance the spark at all or certain RPM ranges. What this means is that the spark plug will ignite and the combustion will begin at a sooner point of the engine rotation. This helps burn the mixture and push the piston back down at the right time to make more power. 

There’s a point at which advancing will do more harm than good. The result will be a loss in power and it can pre-ignite the air/fuel mixture. You shouldn’t need to worry about that on the CRF 230 unless you are running extremely high compression.

ProCom CDI

The best bang for your buck is going to be a ProCom CDI. It advances the spark mostly at low RPM speeds. This will help boost low-end torque, which is where this bike shines. 

The rev limiter is also increased, but the CRF230 is useless at that high of an RPM. Once it goes past 8k it’s going downhill in the horsepower department. 

Exhaust

Did you know that the CRF230F and CRF150F (03-05) share the same size head pipe? Honda wanted to save money, so they didn’t develop a new head pipe that works better for the larger engine, so they used the pipe from the smaller engine. This is a choke point, so going with a larger diameter header pipe will provide a noticeable power gain even if your engine is stock. 

Is The Muffler Junk Too?

The 230 muffler is actually not that bad. Yes, the baffle is somewhat restrictive, but the muffler itself flows well enough to use a larger head pipe with it. 

Going with a full aftermarket exhaust system can yield the most improvement, but it costs more and is generally louder. 

Which Exhaust Is Best?

Pretty much any aftermarket exhaust is going to be better than a stock system if it’s properly jetted. It mainly depends on the look, sound, and price you want to pay for it. 

Cheap Knock-Off Exhaust System

If you’re on a tight budget, the JFG Racing exhaust system is as cheap as it gets while still giving you performance. At about 100 bucks, you wonder how they can sell them… 

The quality of materials and fitment probably won’t be the greatest. You might just need to help it along to fit, but you may not have any problem at all. It’s not a dyno-proven exhaust, so don’t expect massive horsepower gains for your CRF230.

Pro Circuit T4 System

The Pro Circuit T4 exhaust system is my recommendation for the best bang for your buck in performance, quality and price. It looks good and sounds good too. The head pipe has multiple diameters (stepped head pipe gets bigger each section), which is perfect for providing broad, mid-range power. 

Walkaround and Sound Review of Pro Circuit T4

The PC T4 is going to be louder than a stock pipe, but it’s not obnoxious. For around 250, you’re not going to find many other name brand complete exhausts unless they’re used. It also comes with a USFS approved spark arrestor on the end cap.

Yoshimura RS2 System

Yoshimura is well known for making high quality performance exhausts in the dirt bike industry. The build quality and durability is great, and with the quiet insert, it’s one of the quietest pipes while still giving you more power than stock. 

The Yoshimura RS2 Comp Series Enduro exhaust comes with a USFS approved spark arrestor for the CRF230F.

Yoshimura RS2 on CRF230F sound clip

My Personal Review

I personally have an FMF Megabomb head pipe with the stock muffler and a custom end cap on my CRF230F. The FMF header has a reduced diameter where it meets the midpipe/stock muffler joint, so it still restricts flow even though it’s larger than stock up until that point. 

Out of the above options, I would probably go with the Yoshimura or Pro Circuit exhaust system if I had to do it over again. That way I get the whole system without needing to do any mods later to open it up more. 

Carb Upgrade

The stock carburetor is another choke point on the CRF230F. Upgrading to a larger carb will most likely gain horsepower, but you may lose torque if you choose the wrong one. 

XL250 OEM Carb

The old Honda XL250 carb is basically the easiest bolt-on performance carb upgrade for the CRF230. The problem is, they’re hard to find, and they usually need a rebuild with replacement parts that are hard to find in stock. 

The reason why the XL250 carb is better is primarily because of the accelerator pump. The AP is a mechanical pump that squirts a small shot of fuel through the carb at low RPM throttle openings. This extra fuel produces more low-end power and throttle response because it helps get rid of that lean spot. 

Why The Stock Carb Sucks

Old, round slide carbs, like what the stock CRF230F has, are not efficient at low RPM. There’s a lot that goes into that but that’s for another article. If you’ve ever snapped the throttle open quickly from a low RPM, you’ve probably felt the bog or hesitation before it starts accelerating. This is a lean bog because the engine can’t burn the fuel at the same rate that air is coming in.

Adding a little extra fuel from the AP counteracts that, giving you more “snap” at the low-end, which is great for getting up hills in a lower gear or popping the front wheel up to get over a fallen log.

XL250 Chinese Copy Carb

There’s a Chinese copy of the XL250 carburetor on eBay for less than $50, but the quality isn’t quite the same. Many CRF230 owners that have done this carb swap needed to buy two of these carbs and swap out good working parts from each of them to make one complete functioning carb. The accelerator pump and nozzle will probably need to be adjusted as well on this copycat carb or else you won’t get the benefit.

If you like tinkering on stuff and saving money, this route may work out well for you. 

Keihin PWK28 Carb Conversion

A genuine Keihin PWK 28 carb is well known to be a great carb upgrade for the CRF230F, even if your engine is stock. It’s smaller, lighter, easy to tune, and it outperforms the stock carb in every way. 

The biggest setback is the cost and time to adapt it to the CRF230 intake manifold. A new genuine PWK28 is over 200 bucks, but setup with the right jetting and it’s ready to go with some adapters and a different throttle assembly. The stock carb has push and pull cables while the PWK just has one pull cable.

troubleshooting dirt bike carb leaking gas
Genuine Keihin PWK Carb swap on my CRF230F

Adapters are needed because it’s shorter than the stock carb and the inlet/outlet diameters are smaller. They can be machined and pressed on, or you can get creative with some tubing from a local hardware/tool supply store. 

Big Bore Kit

There’s no replacement for displacement. You have a number of options for increasing the engine size on your CRF 230. A big bore piston kit from BBR is available if you want to bore your stock cylinder out. This should be done by a machinist that can hold proper tolerances. 

Athena has a complete big bore kit that comes with a new cylinder and piston kit already matched to size. The best part? It’s not much more expensive than a big bore piston kit. It’s higher compression but can still be run on premium pump gas. To read more about the Athena big bore kit click here

Camshaft

The camshaft is one of the biggest pieces to the puzzle of any 4 stroke engine. It determines where the power is made and how it comes on. Web Cam Racing is the biggest producer of camshafts for the CRF230F. 

If you want more low-end torque, go for higher lift and low to moderate duration. The more duration you add the higher in the RPM range the power shifts towards.

Max lift for the stock CRF230 valve springs is .365″. Any more than that and you will need heavier duty springs so they don’t bind and cause valve float. 

Cylinder Head Porting Is Underrated

The other secret sauce to building a great engine is in the ports. Cylinder head porting can make or break an engine’s power-band, and it’s easy to do the latter if you don’t know what you’re doing. Just making the ports larger probably won’t help as much as you think. In fact, it may make it worse and kill your bottom-end power. 

The Intake Culprit

The weakest link in the CRF230F cylinder head is the intake port. It is restrictive, and unfortunately there isn’t much room to work with before breaking through the port wall. 

Finding a porting specialist that knows the 230 engine specifically is key to getting the most efficient power gains. 

Making Everything Work Together

A stock CRF230 head can only flow so much air. Even if you add a big bore, a larger carb, and a better flowing exhaust, the intake port is going to choke up the potential that you could be getting.

Everything in the engine works together, so if you’re going for a specific type of power-curve, all the components should be tuned for that RPM range. 

Flywheel Key

Similar to the ProCom CDI mentioned earlier, a modified flywheel key can advance the timing to boost low-end power and throttle response. The flywheel key indexes the flywheel, which is on the crankshaft. Removing material from one side of the key will change the timing of the flywheel. 

Adjustable Camshaft Sprocket

Want even more timing adjustability? Slot the cam sprocket holes to “degree in” your camshaft, especially if it’s an aftermarket race cam. It’s always good to check the cam timing and valve clearances when installing a new camshaft. 

Most of the time the cam builder will get the timing spot on, but occasionally you may need to adjust it a couple degrees to get it where you want it. 

Lightened Flywheel

Not only will the engine be lighter, but it will rev quicker for better acceleration. Removing 12+ ounces from the circumference of the CRF230F flywheel is easy with a machinist lathe. The engine and flywheel are already so heavy that removing up to 1 pound will not make it easy to stall due to the lighter rotating mass.

CRF230F Lightened Flywheel

Bonus Mod: Gearing

One more mod that will make a big difference on your CRF230 is changing the gearing. Stock gearing is a 13 tooth front and 51 tooth rear sprocket. First gear is so low that it’s almost unusable. Once you start adding power, you might as well start in second gear because it has plenty of torque to pull it from a standstill.

For more weight savings, stay tuned for Part 2 of the Honda CRF230F performance mods: weight reduction. You can check out the XR200 weight reduction article in the meantime. 

Kelley Fager

Kelley started riding a Honda 50 at the age of 6 years old. The passion for dirt bikes started there and grown into a lifelong pastime of riding and learning how they work. Motocross Hideout is the result of sharing his past, present, and future knowledge and experience.

10 Responses

  1. Itamar Leão says:

    Hi!
    Great post, sir, but everybody says that drill holes in the seat pan is a good thing, but nobody shows a picture of that work! Where to drill, and what is the right size of holes?
    Thanks!

  2. Ryan M. says:

    Thank you for the guide it was wonderful! I however have several questions.

    1) What final drive sprocket ratio do you recomend to fix the unuseable 1st gear issue. (I have also encountered this problem but was unsure what ratio to change it to.)

    2) How specifically did you fit your Keihin PWK 28 onto the current harware. (So I can try to replicate it.)

    3)What jetting do you use for the Keihin PWK 28 to optimize power output? (I don’t have the BBR if that makes a difference.)

    Lastly, a question due to my own lack of knowledge.
    Is the CDI like the bike’s ecu? More specifically does it control more than plug timing, or do I also need to upgrade my coils and wiring harnesses if I upgrade my CDI?

    Many thanks!

    • Kelley Fager says:

      Hey Ryan, thanks for the comment!
      1) It depends on how many mods you have and what kind of riding you do. Just an un-corked and properly jetted CRF230 should be able to pull one more tooth on the front (14T). I currently have 14/49 but plan on going even smaller on the rear soon after some more mods.
      2) It takes 2 custom made adapters. They need to be pressed onto the carb so that the inlet and outlet diameters match that of the stock carb, as well as the overall length the same. I might have the specs written down somewhere… I machined my adapters, but some guys got creative and used cheaper and more simple materials. I’ve heard of some tent poles being the right size if you cut them off.
      3) For my genuine PWK carb I have a 35 pilot, JJL needle in the 1st clip postion, and a 130 main. 1000ft elevation in the summer.
      4} The CDI just controls the ignition. No need upgrade anything else with an aftermarket CDI.

      • Ryan M. says:

        Thanks for answering all my questions Kelley!

        I have a K&M highflow airfilter, along with a fmf powerbomb header and powercore exhaust. I just ordered a genuine PWK carb and CDI, however as is, I agree that first gear is virtually useless. I’ll look into getting a ratio around 14/49, thanks for the recomendation!

        What material did you use for the adaptors? I’m unsure myself as idk what tempature the carb will reach in normal operation, and I have yet to find a guide/tutorial online as to installation. I was looking around the internet for the tent poles story you mentoned but couldn’t find anything about that. Did you just use aluminum pipe that you machined to be smaller? I

        Many thanks!

        • Kelley Fager says:

          Yes, I machined the adapters at my work in my spare time. I’ll see if I can find the overall dimensions if I get a chance.
          I know it was some guys on thumpertalk that made their own as well. There really isn’t a good tutorial on it anywhere…

  3. Jamie Farrow says:

    Kelley, WOW!!! Awesome job and thanks for taking the time to post this. I race flat track and do a lot of single track enduro. Both my bikes are 2012 CRF450Rs, my girls, all 3 ranging from 10 to 2months ride and race, well at least the 2 month old will start riding in a front pack I wear like her 3yo sister did @ 11months, anyways, my 450r woods bike gets real mad at me with all the on off type riding when I’m with them so I bought an 05 CRF230 last week so I can ride with them as a transitional bike and for my wife to upgrade to as well. There’s a lot of info out there and a lot that just doesn’t help a lot! You have provided an amazing resource for the riding community! Thanks again!

    • Kelley Fager says:

      Wow, thank you for such kind words, Jamie!
      Haha, that’s awesome to hear about your girls riding (we’ll be having our first in November, Lord willing).
      The 230 is a fantastic trail and play bike, although I did race a few off-road races with mine.
      Yes, there’s a surprising amount of info on this “cult” bike, which is both good and bad. It can take a long time to sift through to get to what you want, which is where my idea for this article came in.
      I just wanted to take what I have done to mine, as well as what I’ve learned from others and condense it into a detailed, yet easily digestible article.
      I appreciate the feedback!
      -Kelley

  4. Thanks Kelley says:

    Great post. currently have a crf230f motor into a 1985 Honda 200x. Bolts right in other than the cylinder motor mounts.

    I have frame clearance issues if i run the stock carb or a pd pumper and the pwk specs your running in the post was very helpful. Going to give one a try.

    The old cr85’s also use factory pwk 28’s.

    Much appreciated.

    • Kelley Fager says:

      Ah, yes I’ve heard of some people swapping them into those things.
      Yeah, the stock carb is pretty large and cumbersome.
      What are you using for intake adapters?
      Yes, the later CR85 does have the PWK, but I believe it has a different slide as well as jets (a given).
      The slides are pretty expensive, which is why I ordered a new PWK and also had the idle screw installed on the right side for easy access on my 230.

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