Why is My Dirt Bike Leaking Oil

Sometimes oil leaking leads to many problems in a dirt bike. Mostly Fork seal and Shaft seal are the reason for oil leaking. So in this article, we are going to tell you about some steps to fix both the seal and solve the issue of oil leaking in your Dirt Bike.

Once while riding the bike I felt something is falling down and after stopping the bike I found that oil is leaking slowly and that made me crazy as I was in a place where I could go nowhere. Issues sometimes can you make feel annoyed.

Before you meet and caught by this kind of scenario better you should be ready for that. For preparing you to need to understand the reasons behind oil leaking from the bike and how to stop bike engine oil leak.

Why is Your Dirt Bike Leaking?

Oil leaks of the dirt bike could be due to a number of reasons. The multiple reasons can be the failure of minor rubber components like gaskets, connection tubes, o-rings or most importantly seals that can also cause dirt bike engine oil leakage.

  • Wear of Fork seal
  • And Shaft Seal
  • Wear and tear on seal touching crankshaft
  • Failure of Gaskets
  • O-rings wear and tear
  • Connection tubes

How to Stop Bike Engine oil Leak?

Fixing Leaky Fork Seal

You can fix your fork seals in three easy steps. Before we jump into those steps we are going to tell you what tools you need to get the job done right. The tools that you need are a Seal doctor, a rhino, suspension clean paper towels, clip tool, screwdriver, and safety glasses.

1. Preparing the Bike

You’re going to get the bike clean and the port guard needs to come off before moving to other steps.

2. Pulling down the dust seal

What you want to do is, use the clip tool. You could use a screwdriver you want to insert your clip tool or screwdriver gently fall from all the way around and pulling down the dust seal and what that does is get all that dirt and debris sliding down.

You can see there another option is obviously the fork is off the bike it’s a little bit easier to gain access to you’re gonna pull down your dust seal insert and just gently rotate the upper tube and gently fall charmed to pull that dust seal down.

3. Cleaning Under the fork seal

Gently insert that into our oil seal and rotate this 360 degrees what’s gonna happen is dirt and debris is gonna come down gently with from the fork itself and hopefully dislodge any dirt debris sand grit that is causing the fork seal the leak you’re gonna insert your seal.

Make sure that you get it past the spring in the inner lip of the oil. Seal and then you can rotate the upper tube and now you have to clean the excess dirt and spray a liberal amount of suspension clean just to dislodge any of that great dirt debris.

Step 1: Lose the chain then open it

losening chain

Step 2: Uncover the area of engine and open the nut

why is my dirt bike leaking oil

Step 3: Now remove the sprocket

remove the sprocket

Step 4: Now you will see the dirt with oil spread all over.

why is my dirt bike leaking oil

Step 5: open the seal

Step 6: Finally you have to clean seal and inside of the shaft with a rig.

clean seal and inside of the shaft with a rig (1)

Fork Seal Maintaining Tips

If the tube is covered in dirt it’s best just to rinse it off if you’re using a power washer. You should be careful that you don’t point the power washer at the seal or it can force water and mud up underneath the seal.

If you’ve got a lot of dirt on the tube itself just rinse it off with water and then maybe use a sponge with some soapy water but you want to avoid making any scratches vertically because they can make the seals prone to leaking oil.

If you do need to wipe it’s much better there wipe sideways in this motion.

Once you’ve cleaned off the fork you should inspect the tube took the air at the back which is protected by the fort guard.

If you drop it onto rocks or something hard like that I can get scratches or dents and if it’s a very light scratch you can possibly repair it using some very fine sandpaper. if it’s a deeper scratch or certainly a dent you probably have to replace the tube.

When you ride in mud you can find that mud can pack up inside the dust seal and then make its way into the seal and eventually caused an oil leak. So after a mud ride, it’s a good idea to pull the seal down and inspect inside make sure it’s clean inside.

To remove the dust seal you can either use a flat-bladed screwdriver or a special dust seal removal tool that has a thin blade which makes it a little bit easier but whatever method you use to make sure you don’t slip and scratch the fork tube.

So using the tool you just simply insert it between the upper fork tube to the seal and then twist and it’s a good idea to work around and do it in several places.

Then it should just pop straight off and you can see that it doesn’t have any debris down inside the dust seal. So you can just replace or check the other side.

If you want to clean it out so you could use some parts cleaner and compress there blow out any dirt.

Just like leaking of oil, there are so many issues and reasons like going out of a dirt bike which can also trouble you a lot so here we have a complete resolution in this article why is my dirt bike bogging out that will surely help you.

Fixing Leaky Shaft Seal

The symptoms are very very simple you’re gonna see oil around, the chain will start to turn black from the oil and also you will see on the sprocket started to get this little gunk which is the oil that the chain is bringing from around the sprocket and it’s depositing into the rear scrum.

The first thing you’ll have to do is you’ll have to take the chain off and if you have the master link. So for you, it’s very very easy to take the chain off.

You don’t have to take the rear wheel off after that you have a knot over there, which you will be able to take off with a range this is going to be a washer that is specifically designed to hold the nut in place and the sprocket itself there is a special claim that is supposed to hold the seal in place.

By removing the bolts the entire safety plan is going to come off and you’ll see the seal that we were telling you about. The seal needs to be replaced or in some cases, all you have to do is just clean it sometimes dirt and very very fine particle dust will get in between the crankshaft.

Start cleaning it is very very easy. Clean all the dirt and the dust you have around the seal. After that, you’ll put it back in and then you reinstall your sprocket.

So you’ll put your sprocket. then you’ll put your washer and you will put your nut and then you can reassemble the bike and give it a try to see if that’s all it needs because sometimes there are just fine specks of dust that go into that metal piece that creates the problem.

Replacing the Leaky Shaft Seal:

You will want to have some screws, a drill gun some grease, contact cleaner rags and safety glasses. To begin start by making the area of the shift shaft seal accessible.

For this bike, you have to turn the fuel off and then lean it against the bench. Remove the counter-shaft sprocket with a chain if necessary so that you can gain access to the shift shaft seal area.

Before removing the foot shifter be sure to index its position on the shift shaft with the marker. Now remove the shifter, clean the area of the shift shaft seal. So there are a few different styles of these seals now some will be rubber-coated and others will have a metal outer diameter.

Before we begin the extraction process of the old shift shaft seal picks up a screw that is slightly smaller than the width of one side of the seal.

Now you’ll also want to grab a drill bit that is slightly smaller in diameter than the screw itself. Once you’ll drill into the ship shaft seal we can ensure that when you insert the screw that it’s going to get a good bite.

Next, carefully drill a hole into the seal with your drill bit while being mindful not to damage the shift shaft and the engines case also don’t drill too deep to avoid drilling it to something else.

Now set the screw in place, grab the head of the screw with some pliers and pull the seal out now. When it comes to pulling on the fastener to try to get the seal to come out.

It’s going to take a bit of force as the smaller seals do have a more of a like a tight fit. So just don’t give up and keep tugging on it.

Install New Shift Shaft

Before installing the new shift shaft seal make sure that you understand and note its orientation. One side is going to be facing out towards the shifter and another side will be facing in towards the engine lubricated. You have to check it out.

The new seal with grease along with the shaft slides the new shift shaft seal into position. Take your time with this step be careful with it, Make sure to not damage the seal.

Now depending on the type of seal that you have if it’s just a rubber one you might be able to press it into place with just your fingers however with this type of seal we’re going to be using a socket that is about the same size in diameter.

Next, you have to place a deep socket over the ship’s shaft and begin to drive the ship shaft seal into place now you’ll want to drive the seal until it is flush with the engines case you don’t want to drive it in too far.

And make sure that it does go in straight keep in mind that you can damage your new seal and the sealing surface on your case. If you force the seal in crooked once the seals been driven wipe the excess grease off with a rag.

Next, you can reinstall the shifter while being mindful of the indexing mark that we had made earlier you can use some medium strength. Lastly, if you’ve removed it, you can reinstall the countershaft sprocket with a chain.


Leaking of oil from dirt bike can b an irritating event. You must be wishing to get rid of this issue fast. For assisting you we have compiled the post and solve your carry why is my dirt bike leaking oil.

How to stop a bike engine oil leak can be a puzzle for you if you are a beginner. Even a beginner don’t have enough knowledge about tips and tricks how can we understand the technical things which only experience and skilled person can understand.

Therefore we have decided to bring out a good and comprehensive method to understand the issue of engine oil leakage and how to solve it properly. I hope you love this post and if you really like this post then subscribe to our newsletter and also share it with your friends in Pinterest and Instagram.

Sources: How to find oil leaking

Thomas A. Talley

I’m Thomas. Since childhood, I am fond of bikes and hence dirt bikes are my passion now. Ever since then, I’ve been giving advice to the beginners and this has become my hobby.

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