December 23, 2020 7 min read

Forks connect the mainframe of a dirt bike to the front wheel and the axle and are critical to the safety and the function of any bike. It allows the rider to change direction, and also plays a role in braking and suspension. But fork seals are some of the most neglected parts of a dirt bike. So, how do you know if it’s time to replace them? 

When you start to notice oil leaking from the fork seals they are likely cracked. You might also notice that the bike isn’t riding as smoothly as it once was. When you notice these problems, you should replace the fork seals. 

If you’re an avid rider, you need to know how to tell when your fork seals are bad, and when to replace them. When your fork seals begin to leak, it is time to take action. You can replace the seals yourself, you can have a mechanic do it, or you can use the Seal Doctor tool to quickly and effectively solve the issue, and continue riding. 




 

How do I find out if my Fork Seals are Bad?

The easiest way to find whether the fork seals are in bad condition is by checking whether they are leaking oil. To do this, clean the forks with a soft cloth. Then go for a ride and see if they leak oil. 

If you are an avid motocross rider who rides all the time, or you bought your bike second-hand, there is a good chance that your fork seals are leaking, or will be soon. This is because the forks are some of the most neglected parts of a bike, and may never have been replaced or cared for.

Sometimes it can be tricky to tell leaking oil from dirt and other grime. A trick to help you tell if your fork seals are leaking is to take a clean cloth and wipe the lower part of the forks. Once both the forks are clean, take your bike out for a quick spin.  

If you notice oil or grime around the forks at the end of your ride, there’s a good chance that the fork seals need to be replaced. To prevent any further damage, you should get the seals replaced. 



 

Can you Ride a Dirt Bike with Leaking Fork Seals?

When your forks start leaking, it throws your entire suspension setup off. This risks damaging the bike and having the rider become very uncomfortable while riding. Because of this, it’s a good idea to avoid riding a bike with leaking fork seals. 

When the fork seal begins to leak, it lets air into the oil reservoir in the tubes of the fork, which in turn, lets oil get past the seals. This is an issue because it means there is less oil in the oil reservoir, it affects the valving action.

If this is all getting a bit too technical, you can think about the forks like shocks on a car. When a car shock blows, it causes the car to bounce clunkily down the road, because the suspension springs are not dampened. This is exactly what happens when the forks on your bike aren’t working as they should. The wheel will bounce, instead of riding smoothly.

You can ride a bike with leaking seals, but it may not be very enjoyable, and you shouldn’t let the seals leak for too long. The more the fork seals leak, the more you are putting your bike at risk of damage. You don’t need to replace fork seals the second you notice leaking, but get it done as soon as you can to avoid further damage.




 

Is it Normal for Fork Seals to Leak a Little?

It’s common for the forks to leak a little. The longer it continues, the more risk of damaging the bike. Because of this, you should get the forks replaced as quickly as possible. 

Oil leaking from a fork seal is a sign of larger issues with the suspension. Some riders believe that they cannot notice a big difference between different levels of suspension but for most riders, the difference is obvious.

 It is common for fork seals to leak, but it does mean that it’s time to take action. Even a small amount of leaking can lead to bigger problems, so replace or repair your fork seals as fast as you can to prevent further damage and uncomfortable riding.




 

When Should Fork Seals be Replaced?

If the forks are leaking, you don’t have to jump to conclusions and spend money to get the seals replaced. 85% of forks seal leaks are caused from dirt and debris getting into the seals, creating areas for the oil to leak through. The Seal Doctor, a tool we will talk about in a minute, can help stop leaky fork seals immediately, and save yourself a lot of money in the process.

If your fork seals are leaking, that’s a pretty clear sign that you need to repair them. But you can see more subtle signs that they need to be replaced or repaired. If you wipe a cloth along the rim of the seal, and it comes away with oil on it, the fork seals are beginning to deteriorate.

Often, bike riders will find that fork seals leak several times each year, and the repair and replacement of these parts can be challenging. Having the right tools to quickly and effectively fix a leaky fork seal can be a game-changer, and help you continue riding without interruption.

The Seal Doctor is a great tool to help you get back to riding quicker, by fixing a leaky fork seal without the need to fully replace the seals. All you need to do is snap the Seal Doctor onto the fork and twist. Not only will this prevent further leaking, but it will also pull the dirt out of the fork. You can see more about the Seal Doctor here.

Once you’ve replaced the forks, they will be able to last for a long time. Precisely how long they should last will depend on the type of bike you have and how you use it. 



 

How Hard are Fork Seals to Replace?

As long as you have a little mechanical experience, you should be able to change the fork seals yourself. However, if you aren’t confident in the process, you can call in a mechanic or a suspension technician to change the fork seals for you. 

For those with a little mechanical experience, replacing fork seals may not be too challenging. The first step is to loosen the upper triple clamp’s pair of bolts, to release the fork legs. You will then need to loosen the fork cap on the top of each leg. You don’t need to unscrew them, just loosen them so that you can access the fork seals. Keep in mind that if you have air-pressurized forks, you will need to bleed the air pressure out before you can loosen the screws.

The next thing you’ll need to do is loosen the brake caliper bolts, as well as the front axle. You will then need to prop the front end of your bike off the ground safely, with something like a front end life or another tool.

You will then need to remove the brake calipers, as well as the speedometer cable, front fender, and front wheel. You might also need to take off the brake hose clamps, depending on the model of bike you are riding.

The next thing to do is to remove the fork cap, which needs to be done with care. The upper half of the fork needs to be placed vertically in a soft-jawed vice. Chrome plating can be easily scratched, so be mindful of that when you place the dirt bike in the vice. Remove the fork cap and the spring, and then drain all the oil into a container. The fork needs a few strokes to remove all the oil.

The fork will only extend to a certain amount before it stops. There is a dampener rod that holds the two rods together. There is also a socket-head screw that runs through the outer leg of the dampener rod. The fork halves need to be separated which means the hidden bolt at the bottom of the outer tube has to be removed from the dampener rod.

With the legs apart, you can clean and inspect the inside of the forks. You can clean or replace the fork seals, and put your bike back together again.

If you are concerned about replacing your fork seals successfully, you may want to call in the help of a mechanic. Alternatively, you can use the seal doctor to fix leaky seals and get back to riding much faster, and with much less fuss.

Personally, when it comes to getting your suspension rebuilt and revalved, I suggest letting a professional do it. If done incorrectly, it is very noticeable and can make your suspension unrideable.



 

Final Thoughts

Fork seals are a vital part of any dirt bike and allow for smooth suspension and an enjoyable ride. If your fork seals are beginning to leak, you are advised to find a solution as soon as possible. You can undertake the arduous task of replacing your fork seals on your own, you could pay a mechanic to ensure the job is done correctly, or you could use a Seal Doctor to solve a problem in a matter of seconds. If you love to ride, and you want the quickest way to effectively contain leaking fork seals, letting you continue riding, the Seal Doctor could be the answer.


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