4 Best Free WR250F Mods To Make It Faster

Looking for the best WR250F mods to make your dirt bike faster or more comfortable? Whether you have a first generation WR or latest generation, you're in the right place!

In this article, I'll show you the best free mods as well aftermarket parts that actually make a difference, why some upgrades work better than others, and how to easily make your WR250F work better based on your specific needs.

4 Best Free WR250F Mods

These first 4 mods are FREE, although most of them only work on the earlier model years. So if you want to give your "choked up" enduro bike a little bit more "oomph" in the power department, then you should carefully do these simple modifications:

Air-box Mod

The stock air-box on your WR250F dirt bike has a snorkel/shield that helps protect the air filter from water, sand, and other foreign materials. Although it is safer on your filter, it also robs usable horsepower because it blocks air-flow.

To change this you just unscrew it and pull the screen out. This mod will make it more like the YZ250F because it doesn't have the screen in it. If you go out to the desert or a dusty track and want to protect the air filter, simply screw back in the screen.

Doing this mod will make more of a difference on the 2001 and 2002 models because the newer ones have a battery in the air-box that restrict air-flow.

Un-corking the Exhaust

The exhaust baffle on the WR250F is very restrictive because it has to be quieter and have a spark arrestor for legal trail riding. The exhaust hole is very small, taking away a lot of power from your dirt bike because it can't flow as much exhaust through and out.

To remove the baffle you must take off the 10mm bolt on the end of the muffler that keeps it there. Then just slide out the baffle and you will have instant power gains.

Should you remove the exhaust baffle?

Although doing this give the bike more power, it will be considerably louder, so keep that in mind if you ride close to crabby people that don't want people to have fun these days.

If you want to buy a silencer with a spark arrestor that keeps the bike quiet, yet still gains power, an FMF Q4 slip-on exhaust (Motosport) is an excellent choice.

CDI Gray Wire

The gray wire on a WR250F from the CD ignition box connects to the ground. The gray wire is what makes the WR250F's timing differ from the YZ250F. It retards the timing on the mid-to-top-end of the RPM range, thus making it a slower and more poky ride.

To give it more power in the upper RPM range you simply have to get rid of the gray wire. You can either cut it, or take it off and cover it with some tape.

Finding the grey wire

To get the the wire you have to take off the seat, the tank, and the radiator shrouds. Find the CDI, which is a black box (on the right side of the steering stem for '01-'02 models).  There should be two different groups of two wires coming out of the CDI.

The kill switch has a black wire and a black wire with a gray stripe. You want the other group with a black wire and a gray wire. It should be under the frame where the gas tank is.

Unplug the connector and pull off the dust ring. Plug the connector back in and tape up the wire you just took off to the connector. Then you just slap the tank, shrouds, and gas tank back on and you're good to go.

Throttle Stop

Who wants to be restricted, especially on a dirt bike?? I know I don't, and that's why one of the first things I'd do on a WR250F is get rid of the ridiculous throttle stop that limits it to ¾ throttle.

To get rid of this you must go to the right side of the carburetor and take off the throttle cover that has a couple of allen bolts. The throttle is a screw on the bottom of the throttle disk, as shown in the picture.

Cutting WR throttle stop screw to length

To modify it to the length of the YZF throttle stop, take it out and cut it with a saw. The original size is in between 30 and 35mm, so cut it to about 25mm. Put the throttle stop back in and that's it.

If you want to confirm that you're getting 100% throttle opening, you'll have to take the carb off the airbox and turn the throttle to see the throttle slide go all the way up in the carb bore.

What will these free mods do to your WR250?

After you do these mods your bike will be about as close to a YZF motocross bike as you can get. There are a couple more modifications you can do to your WR250F, but they require some special tools and a little extra cash.

Now it's time to look at even better upgrades that cost some money but can also make a big difference, especially if you have a newer WR 250F!

The Best WR250F Aftermarket Parts & Upgrades

Whether you want to make your Yamaha WR250F faster for off-road racing or just more comfortable and safer for enduro and trail riding, these are the best mods that I'll cover in more detail:

• Suspension upgrade for your weight
• Exhaust upgrade for more power
• Engine mods for more torque & horsepower
• Enduro mods for off-road riding

Suspension upgrades for your weight

Getting your suspension tuned and set up for your weight can make a huge difference in how your WR250F handles. Not only will it give you more control, but you’ll have more confidence to ride faster!

First, you need to make sure you have the correct spring rates in your shock and forks. If the springs are too soft, they will ride too low in the stroke, making it feel harsh and bottom out too often.

When the springs are too stiff, the suspension will stay too high in the stroke (travel), making it bounce off small bumps more and be harder to turn because you can’t get enough weight on the front-end.

Once you get the right springs (stock is usually good for 150-190 lb riders depending on your speed), then you need to get the suspension balanced to make it handle well.

Rear shock

First, you need to adjust the ride height so that the front and rear are balanced. The shock sag controls the ride height, which is adjusted by turning the preload nut on top of the shock spring.

When the rear is too high or low, it will either be unstable or difficult to turn. After you get it balanced (use OEM service manual for sag numbers - 100mm sag is a good starting point)., then you can adjust the clickers.

Turning the clickers in or out controls how fast the shock compresses and rebounds - it’s like a free re-valve if you just take some time to test.

If the clickers don’t make enough of a difference, then it might be time to send your suspension to a tuner. You can also buy a Race Tech Gold Valve kit (Motosport) if you prefer to DIY and learn how your suspension works!

Front forks

Since the preload isn’t as easy to adjust on the forks, the easiest way to tune it is with the clickers or changing the fork height. You can raise or lower the forks in the triple clamps to change the front-end height for more or less stability - just make sure you keep both forks at the same height and write down your numbers if you want to change it back!

The best aftermarket exhaust for your WR250F?

The stock exhaust is definitely a weak point on the WR250F when it comes to performance. If uncorking the stock exhaust wasn’t enough, then there are several aftermarket options from slip-ons or headers, to complete systems that shed weight and add power (and noise!).

FMF Factory 4.1 slip-on

Top of the line muffler, FMF’s Factory 4.1 slip-on (Motosport) is made for power. It’s much lighter than stock, although it is noticeably louder.

Pros:

• More power
• Better sound
• Less weight
• Looks better
• Quality fit & finish

Cons:

• Louder than stock (especially with spark arrestor screen/baffle removed)
• Expensive

FMF Q4 Hex spark arrestor slip-on

Want more power but less noise? The FMF Q4 spark arrestor slip-on (Motosport) may not be as quiet as the stock WR250F muffler, but it’s pretty close and gives you a slight bump in performance while still being trail-legal.

Pros:

• Quietest aftermarket exhaust
• More power than stock
• Less weight
• Looks better
• Quality fit & finish

Cons:

• Expensive
• Not as much power as other exhausts

Yoshimura RS-4 slip-on

Want to try a Yoshimura RS4 slip-on (Motosport) for that different factory look at sound? It’s a quality muffler that’s built for off-road racing.

Pros:

• More power
• Better sound
• Less weight
• Looks better
• Quality fit & finish

Cons:

• Louder than stock
• Expensive

FMF Megabomb header (Ti or SS)

For the lightest and best aftermarket head pipe, the FMF Titanium Megabomb (Motosport) is your best choice. It’s as close to “factory looking” as you can buy, and the price shows it…
Or you can go with the slightly cheaper Stainless version that weighs a little more.

Pros:

• More power
• Lower sound
• Less weight
• Looks better

Cons:

• No heat shield included
• Expensive
• Dents more easily

Pro Circuit Ti-6 complete exhaust (or standard T-6)

For an overall boost in performance, a Pro Circuit T-6 (Motosport) is a quality choice - there’s a reason they’ve been around for so long. And if you want the Titanium option that will turn a ‘cool blue’ over time, it will make your bike (and wallet) lighter.

Pros:

• Cheapest full exhaust
• Good power & throttle response increase
• Less weight
• Titanium looks “cool”
• Quality fit & finish
• Removable USFS-approved spark arrestor for trail riding

Cons:

• Louder than stock

FMF Factory 4.1 RCT complete exhaust (Ti or SS header)

For the full FMF Factory 4.1 system (Motosport) you get the full performance advantages over stock - even more power and less weight. 

Pros:

• Cheapest full exhaust
• Good power & throttle response increase
• Less weight
• Titanium looks “cool”
• Quality fit & finish
• Easy to change inserts for sound or adding a spark arrestor

Cons:

• Louder than stock
• Expensive
• No spark arrestor included

Which is best for you?

Best cheap WR250F full exhaust: Pro Circuit T-6 complete exhaust

Best WR250F exhaust for off-road racing: FMF Factory 4.1 Ti complete exhaust

Best Quiet WR250F exhaust upgrade: FMF Q4 Spark arrestor slip-on

*By clicking through these links and buying your exhaust, you support me (Kelley) in growing Motocross Hideout - thank you, I really appreciate your support!

Big bore kit

Want more power or need to rebuild your 4 stroke top-end? Adding displacement is the easiest way to get more power, but is it actually worth it?

Well, if you need a new piston and cylinder, then it’s definitely worth upgrading to the Cylinder Works 270cc big bore kit (Motosport). It comes complete with everything you need.

It’s just as easy to install as an OEM piston and cylinder - just follow the OEM service manual step-by-step.

Is a big bore kit reliable?

Heat is the #1 enemy of a gas engine, and a bigger bore will create slightly more heat at the same RPM as a stock bore 250cc WR250F. However, with considerably more torque, you don’t need to rev the engine as high to go as fast.

With such a small increase in diameter and being able to ride at a lower RPM, a quality made big bore kit, such as the Cylinder Works kit, is just as reliable as stock if you install it properly and maintain it.

Does jetting need to be changed with a big bore?

Yes, since your bigger engine will be sucking more fuel through the carb (or fuel injector), you’ll likely have to lean the jetting or mapping out. There are some common symptoms that tell you whether it’s rich or lean.

Do I need other mods with a big bore?

If you change nothing else, you'll get a big increase in low-end torque with very little to no top-end horsepower gain. This is because the intake, cylinder head/cams, and exhaust are tuned for 250cc.

When you increase the engine size, everything else is choking the engine potential. That's why you get even more power gains with a bigger bore when you install a better flowing exhaust, bigger cams, and get the head properly ported for the RPM range you want.

Camshaft

Looking to improve torque and horsepower in addition to an exhaust and big bore kit? A Hot cams stage 1 Exhaust cam (Amazon) with auto decompression is a bolt-on mod - you just need to check valve clearances after installation.

It fits 2001-2013 WR250F engines and adds the auto-decompression mechanism that the 2001-2002 engines don't have, making it easier to start.

Higher flow air filter kit

Considering cutting out the mesh screen behind your air filter to get more power? 

The Twin Air Power Flow air filter kit (Motosport) not only gives you more power and throttle response, but it's safer than cutting up your screen and hoping leftover chunks don't get sucked into the engine.

Best WR250F Mods For Enduro

Maybe you don’t need more power, but rather some essential accessories that make enduro riding on the trails or desert more fun and safer.
These are the top WR250F mods for enduro:

Oversize tank

Want to ride further without needing to re-fill? Whether you’re out in the desert or mountains, an Oversize Gas Tank (Amazon) is the easiest way to do it without hauling gas on your back all day.

For a couple hundred bucks, you can hold at least 1 gallon more, allowing you to ride an extra 30-40 miles further. Just make sure you get the correct tank for the generation Yamaha WR you have.

Yamaha WR250F generations:

• 1st gen: 2001-2002
• 2nd gen: 2003-2006
• 3rd gen: 2007-2014
• 4th gen: 2015+

Hand guards

If you’re riding in the woods or anywhere there’s trees and bushes, you’ll want some quality hand guards to protect your hands and fingers. The Acerbis X-Factor handguards (Motosport) are a good combination of protection without looking obnoxious.
They’re nice and lightweight, as well as small and easy to mount to ⅞ or oversize handlebars.

Flo Motorsports radiator braces

One major potential problem on all liquid-cooled dirt bikes is the radiators getting bent and leaking. You can prevent that with a sturdy set of Flo Motorsports radiator braces (Motosport) without compromising the cooling efficiency.

Not only are they stronger than a typical radiator guard, but they flow more air, which is super important if you’re riding tight and technical trails, such as hard enduro riding.

Trail Tech Fan kit

Instead of spending several hundred dollars on an aftermarket water pump kit and larger radiators, you could just buy a Trail Tech Fan kit (Motosport) that does an even better job of keeping your dirt bike cool.

Riding slow speeds is a common cause of overheating a 4 stroke, but the fan helps pull more air through to cool it down and prevent coolant steaming out. Another common cause is poor clutch control that heats up the entire engine quickly.

GPS Speedo dashboard upgrade

Looking to upgrade your WR250F speedo dashboard? The new Trail Tech Voyager Pro (Motosport) has GPS made for off-road motorcycle riding, and the latest “buddy-tracking” system is super nice if your friends have one so that you never get lost!

In addition to those special benefits, you get everything a dirt bike speedo should have and more, including warning lights if your coolant temp is getting too hot.

Battery upgrade

The WR250F commonly has battery and starting problems, but an upgraded battery can help solve that - especially if yours is dying anyway! The Fire Power Feathweight Lithium Battery (Motosport) is not only stronger than stock for easier starting, but it sheds a few pounds of weight instantly for better handling!

Clutch upgrade

Want a better feeling or longer last clutch? The stock clutch is pretty good on the WR 250F, but there’s room for improvement if you abuse your clutch.

Manual clutch

The Rekluse Core manual clutch kit (Motosport) is a nice upgrade over stock because it’s more durable, has a better feel when slipping it out of corners, and the clutch pull is actually lighter than stock! 

Yes, it’s an expensive upgrade, but how often are you changing your clutch pack? For racing at a high level, it’s definitely a mod to consider.

Auto clutch

Maybe you don’t want to have to deal with a clutch lever. In that case, the Rekluse RadiusCX auto clutch kit (Motosport) is an amazing upgrade because it can instantly make you look like a better rider!

When properly set up, it slips the clutch more efficiently and can engage almost instantly for a good low-end feel in power. Your clutch can actually last (much) longer if you don’t have good clutch control, which reduces your parts bill and your chance of overheating your dirt bike!

Fender Bag

For enduro riding on the trails or in the desert, it’s smart to have a trail pack of tools. If something breaks, you need to be able to fix it or else you’ll be stranded.

That’s why the Giant Loop fender bag (Motosport) is a great upgrade for your Yamaha WR250F. It’s easy to install, it’s sturdy, and can carry a lot of small essential tools for trailside repairs.

The best mod to give you confidence & control

All of these free mods are good for your WR250F, but there's something that will greatly improve the speed of it on the trails or riding off-road.
What is it?

A better rider. What does it take to become a better trail rider? Learning how to properly control your bike with good riding technique. Want to get started by reading my training guide in just a few minutes? Click here to learn more.