How To Replace a Dirt Bike Chain and Sprockets

The time has finally come.

You’ve worn out the chain, and sprockets on your dirt bike.


You want to know how to remove, the old stuff.  To replace it with new.

So, let’s get started.


How to change a dirt bike chain and sprockets

Changing the chain and sprockets, on your dirt bike can seem like a tough task at first, and it sure might not be the quickest job.

But, once you get the concept down, and more familiar with the process.  It will become like old hat.


Something to keep in mind,

It’s always best to replace chain and sprockets at the same time.  Using worn sprockets with a new chain.  Will prematurely wear out the chain, and vise versa. As they develop wear patterns together.

Another point I should mention real quick is, make sure you run the same width and pitch chain and sprockets together.  A 520 chain with 520 sprockets.  525 chain, with 525 sprockets etc.


Before you start turning wrenches,

Always refer to your owners and or service manual. For your make and model dirt bike.  For specific safety and repair instructions.  and the nut and bolt torque values.


Ok, First off you want to,

Put the bike on a stand.

So you can spin the rear tire

To get to the front sprocket.  You will have to remove, the chain guard or cover.


 Loosen the counter shaft sprocket.

Now, different bikes will take different tools.  To remove the counter sprocket

They could have a snap ring, couple small bolts, single bolt with washers, or a big nut.

If, you have a bolt, or nut setup, before you take the chain off.

Have someone hold the rear brake to help hold the counter sprocket still.  So you can break the bolt (s) or nut loose.

Loosen it up good, or take the bolt all the way out of the counter shaft sprocket.


If you have a counter shaft sprocket tool you could just remove the chain, because it will allow you to hold the sprocket from turning.



Remove the old chain

First off,

You want to loosen up the rear axle nut. Then loosen the nuts on the chain adjust bolts screw the adjuster bolts in to get the tension off the chain.


Find the master link clip or the rivet link. So, spin the tire by hand until the master link is at the top or back of the rear sprocket (somewhere you can work with it easy)

Working off the sprocket makes things easier by helping keep the chain in place

If you have standard style non sealed MX chain.  With a master link clip, just use a pair of pliers


A pair of master link clip pliers if you have a pair, even a flathead screw driver will work put it up against the end and lightly tap it back with a hammer to remove it. Then pop the master link out and remove the chain.



If you have a riveted master link you will need a chain breaker.

Which a lot of bikes come from the factory with a rivet style master links.

Or if you have an O ring or X ring chain.  They have an outer link plate with a tight pressed fit.

So let’s talk about,

Removing a riveted (or pressed fit) master link

Even though a robust (quality) chain breaker can usually handle pushing the pins right on out.

Some people like to take a small body grinder, and grind the face of the pins off, down to the surface of the outer link plate.  To help  increase the service life of the chain breaker.

Then take the chain breaker and press the pins out.



Maybe you don’t have a chain breaker yet?  You may have to grind down a little more on the pins.

Sometimes even half the original thickness of the link plate to get the outer link plate off easier.

Then, once you locate the pins on the ground surface (which can be difficult with the grind marks).

Take a punch smaller than the diameter of the pins

And then,

Lightly tap the pins out, or you can tap an old flat head screwdriver, between the outer and inner link of the chain, and it should pop off.

So, once you remove the master link remove the old chain by pulling back toward you out the top of the swing to remove it.

Just reverse this process to put the new chain back on.


So once the chain is removed lay it off to the side


Remove and Replace front (countershaft) Sprocket

Now, you can remove the old counter shaft sprocket just pay attention to the orientation of how the old one came off.

So you put the new sprocket back on the same way. Keep track of any washers spacer and where they go.

To make sure you have proper chain and sprocket alignment.

Always a good idea, while you’re in there to check the countershaft seal.

If it looks like its leaking now would be a good time to change it if it looks good clean up any gunk on the case and…

Reinstall the new countershaft sprocket on the shaft.

Just remember,

Wait until after you get the new chain back on and connected.

You can have someone hold the brake again. Then you can put some medium strength blue loctite on the threads of the bolt (if you have that style) and tighten down, and torque it.



Now loosen up the

 Remove the Rear Sprocket

You can take the rear sprocket bolts loose while still on the bike which makes it easier. So you have less to hold on to.

That way the wheel isn’t moving all around on you. Like it would if it was off and have it loose on the floor.

Always try to tighten, and loosen the bolts by the nuts on the back of the rear sprocket,


Because, the Allen or Torx heads of the bolts, can strip out easy.

After the bolts are loose.

Then remove the rear wheel from the bike.  And then finish removing the sprocket

Now that you have the sprocket removed.

You can…

Reinstall The New Rear Sprocket.

You can reinstall the new sprocket. Just make sure the mounting surface is clean and smooth with no burrs or bumps.

With the counter sunk holes facing out.  Lay the sprocket on the mounting surface  of the hub and move it around a bit.

Just to make sure it sitting nice and flat.

You really should always replace the bolts when replacing the rear sprocket, and make sure you have the ones made for your bike, because

Bolts that are too long or short, and or they have messed up threads, heavy corrosion.  Or the head of the bolt (allen or torx) is rounded out it will all cause problems.

Plus if the taper on the bolt is worn from coming loose at one time.  Also if they just have the wrong taper on them they can come loose and you sure don’t want that to happen.

If you do have to use the old bolts (if they are correct and still in good shape) clean them up good

Then reapply some medium strength (blue Loctite) thread locker on the threads

Now, if you want you could also apply some medium strength thread locker on the taper of the head of the bolts. Where it mates to the sprocket.


After you put all the bolts in the sprocket, starting them by hand.


You can begin to,

Tighten the rear sprocket down.


Snug them down lightly (in a criss cross pattern) with a ratchet and wrench and  then torque the bolts in a crisscross (star) pattern.  This will help to tighten the sprocket down evenly.

Refer to your service manual.  For the recommended torque specification for the bolts.

Remember when you tighten the bolts take it easy on the Allen heads. Try to tighten mostly via the nuts.

You might want to remove and lube up the chain adjuster bolts.  Before installing the rear wheel.  To prevent them from corroding up.

Also most of the time its recommended to put a thin film of grease on the axle so it doesn’t rust.

So put the wheel back on the bike, but don’t tighten the axle bolt all the way down.

Leave it a bit loose though, so you can slide the wheel back, and forth to adjust the chain tension


Inspect chain guides, slider, and rollers

This would also be a good time to inspect all the chain guides, sliders, or rollers and replace if necessary

Most chain sliders wear at the front part of the swing arm and you don’t want it to start eating down into it.


Now, Let’s talk about,

Chain length

Generally you could just refer to your owner’s manual for the proper length chain.  If, you will be running, the same size sprockets that came stock on your bike.

Also, sometimes you can purchase a chain and sprocket kit.  That has the chain made to the right length.

Most aftermarket dirt bike chains come with 120 links to give you plenty of chain to fit your application.  Since they don’t know your bike make and model, or your sprocket sizes.


Because if you did….

 Change sprocket size?

This will change the length of your chain.  So, you will have to see where you are at with the length.

When cutting the chain to length.  Now keep in mind a chain has a inner and outer link.

So when removing links you will be taking two links off at a time (in a pair).

You will need to have, two inner links facing each other. To be able to connect the master link. The master link is a outer link.  Chains will always have a even number of links.  Just the way it works.


To put you roughly in the ball park.

For every 1 to 2 teeth you add to the front or rear sprocket you need a chain 2 links longer.

Add three to 4 teeth you will need 4 links longer etc.


What happens if you go with less teeth on the front and rear sprocket.

So for every 2 to 3 teeth, you reduce on the front or rear sprocket, remove 2 links of chain.  Deduct  4 to 5 teeth, remove 4 links of chain etc.



Hold your chain links for a minute.  A note of caution though

 Start with a longer chain

Always start out with a chain longer than you need it, and then bring it down in size.

Also, always best to leave a chain longer, than you need it to be at first. Then making it too short.


Well, because you can always take a little extra off, but there is no way.  To safely add links back to a chain.  Measure three times cut once.

If, you make the chain too short you will have to buy a new chain and start over.


So, always double, and triple check length, by putting the chain on the bike and checking length.


But first,

Position the rear wheel 

Some riders put the rear wheel all the way forward, in the swing arm.  This will give you the most travel for adjustment (rearward) in the future as the chain wears.


Some people like to set the chain length with wheel in the middle of the chain adjuster slots.  This will allow you, to make the wheel base a tad longer.

Which can help improve handling, but the downside is you will run out of adjustment quicker when the chain wears.


Another good thing about the middle position is, if you cut the chain a bit short.  You might be able to slide the wheel forward enough to get the proper chain slack back.

The middle is a good recommended place to start. Giving you some travel forward and back.

So, position the wheel where you want it.  All the way forward or in the middle or somewhere in between the two.

Grab an open end wrench for this. That is the correct size you do not want to round off the head of the nuts or bolts.


Screw the chain adjuster bolts in on both sides equally.  Until they’re at the position you want them.

Push the wheel forward until the axle blocks are up against the chain adjuster bolts.

Then, Put the chain on the bike roll it around front and rear sprocket and bring it back to itself on the top of the rear sprocket. Just flip the extra links up.


Now you need to,

Mark the Chain 

So take up the slack out of the chain, but hold up a minute.

Caution: You need to make sure you still have enough for the proper amount of chain slack.

Always refer to your owners manual for the proper amount of chain slack for your bike and where you should measure it from.

Usually for most bikes you measure chain slack right in the middle, (center point) between the front and rear sprocket on the swing arm

Like mentioned above It’s best to leave the chain a little bit long. Take your time, to get the length right, because you can always take more links out.


So, once you find how much you need to remove, mark the link with a sharpie marker.

You may have to clean the grease off the link.  For the marker to stick though.


Now if you have, a

Little extra slack?

Don’t worry if you get the chain slack close, but you still have a tad bit too much slack.

The fine tune adjustment can be done with the chain adjuster bolts. Moving the rear wheel back. Which we will get to further down.


Now once you get the new chain marked to the length and figure out what chain inks that will need to be removed


Remove excess links

Just like you did if you had to remove an old o ring or x ring chain. You will have to grind the outer link pins you marked and get the chain breaker back out. Which is the easiest way.

Remove the chain off the bike.  If you don’t have a chain breaker.  And as mentioned above. You will have to grind the pins down more on the outer link plate sometimes nearly half of the original thickness.  To get the pins out of the link plate easier.

Then you will have to try to locate the center of the ground away pins best you can.

Then use a hammer and a punch to lightly tap the pins through.

Ok so now that you removed the excess links you don’t need.


Install The New Chain

Feed the new chain back through roll it back around the sprockets.  Bring the chain back to itself at  the top of the rear sprocket teeth  So you can put the master link in.

To be cool make sure to put the lettering.  On the chain facing up (so it looks nice)


 Install the master link on a Standard Chain

With a standard chain.  Put some lube (grease) on the pins and reinstall master link.  In through the backside.

It’s just easier, to install the the outer link plate and master link clip.  On the outside (with the pins facing you).

Now, you’re ready, to put the master link clip on the pins.

Using vice grips, or needle nose.  Can usually, get the job done.

Or a pair of master link clip pliers.  If, you want to make things even easier.

Just make sure, you put the master link clip, (keeper) on the right way.

With the closed off end, facing in the forward drive direction. Why does this matter


This will keep the clip from being knocked off.  By stuff when riding down the road, track, or trail.

Also make for sure the clip is fully seated, in the groove properly.

Now, if you bend or damage the clip.  When trying to put it on.  Get a new one and try again.

You DO NOT want to use a compromised clip.   It could fail and fall off.


Do You have a

 X ring or O ring chain?

So if, you have a o-ring or x-ring chain.  Make sure the o rings are installed on the master link pins.

Then put the master link in through inner links from the back side to connect the chain.


Put the greased up o rings on the pins, that are sticking out of the inner links, facing you.

Then install the outer link plate on the pins.

O ring and x ring chains.  Like mentioned above have a tight pressed fit.  On the outer link plate.


You could fumble around, and try to get it on, with a pair of vise grips (locking pliers), and try to slowly work the plate on,


It can be frustrating and difficult.  Also if you’re not careful.  You could bend or warp the side plate, (outer link) so its best avoided.

Having a quality chain press.  To put the outer link plate back on.  Will make it a lot easier.

Also when pressing it on,

Don’t press it on too far though, because you could over smash, and damage the o rings.

Or make the chain link too tight.

Take your time, and just press it on just far enough.  That you can get the master link clip on.

(the link plate will be flush with the neighboring outer link plates)

You can also check the link width, with a caliper.

Measure from outside to outside, of the side (outer link) plates. Make the master link width the same.

Also make sure,

The clip is, properly seated in the groove.  With the closed off end of the clip facing in the forward drive direction.


Did you,

Switch from a standard chain to X ring or O ring?

If you put an o ring chain on a bike that didn’t have one originally.  Because an o ring chain is wider than a standard (non sealed) style chain.

You could sometimes run into clearance (rubbing) issues on the engine case,   So alway keep and eye for that when you put the chain on.

Or, even do some research before hand and see if any riders have had problems with the bike you have.

You may have to put a spacer behind the countershaft. Something like a Fastway countershaft spacer.

To bring the chain out away from the engine case a bit,  And or you might have to run a DID narrow X ring chain.



Do you want a…

Rivet Link?

Now, if you want a riveted master link (endless chain).  You will have to have a chain tool, with a rivet tool.   A riveted master link, is stronger, and less likely to have a master link failure.  Now if, you want to know how to make, a riveted master link.  Click here



Check Chain Tension (Slack)

Always refer to the owners manual.   For the exact specs, on where you should measure the chain slack, and how much chain slack.  You should have, on your dirt bike.

The best, and most consistent way.  To check chain tension, is to use a slack setter. Or, you could do it old school.  With tape measure or ruler.

You need to be in the center of the chain.  Between the front, and rear sprocket

Take a tape measure, if you want to be more precise, and measure the distance from the center of the rear axle.  To the center of the front sprocket.  Then divide it in half.  To get your center point.

On most dirt bikes, the center point is usually on the back edge, or just right behind the chain slider.  On the top of the swing arm

Then pick up on the chain (at the center point).  Till it’s taught, and measure the distance between the swing arm and the bottom of the chain.

Now these specs will vary from bike to bike, but most the time.  They will call for roughly around, 48-58mm (1.9 to 2.3 inches)


How do you,

Adjust Chain Tension?

Now, if you weren’t able to land a perfect slack adjustment.  When you cut your chain to length, and need to take up a bit of excess slack.

Just run the adjuster bolts back out, evenly on both sides.  Until you reach the proper chain slack.

Just remember to Be careful

DO NOT make your chain too tight. it could cause transmission or engine case damage.  Or bust a chain.  Too loose and it could derail.


Also, before you

Tighten the axle back down.

Make sure the axle blocks are up against the head of the chain adjuster bolts, on both sides.

You can do this, by putting a folded up rag.  On the top, between the chain and rear sprocket teeth, and pull the tire back.

This puts tension on the chain, and pushes, the axle blocks forward.   Up against the adjuster bolts.

Make sure the index marks, on the axle blocks (adjuster plates).  Are aligned with the same marks. On both sides of the swing arm.  This is to make sure that the rear wheel/sprocket are tracking straight.

It’s even best to make sure it’s even.

To measure both sides from the center of the rear axle.  To the center of the swing arm pivot shaft.  With a tape measure.  Because the marks on the swing arm are not always right.


Now, tighten and torque the axle nut to proper specs.  Just recheck wheel measurement again.  To make sure nothing moved.


Tighten the  jam nuts, on the chain adjuster bolts, on both sides.

Hold the bolt with one wrench, and jam the nut with another.


Look down the chain.  From the back to front (countershaft) sprocket.  To make sure the chain comes off the rear sprocket straight.  Or use a chain alignment tool.

A misaligned chain and sprocket can cause excessive wear.  To the chain, and sprockets or even  possibly worse derail.

Always recheck, all your work,


Also make sure the chain tension (slack), is proper before you ride.