The chain and sprocket on your ATV will no doubt wear out over time. The teeth on the sprocket get worn down and dull, and the chain will tend to stretch over time. Other than buying high quality parts, there’s not much you can do about it either, it’s just normal wear and tear.
Maybe you don’t have worn out parts, but you want to change out your sprocket to adjust your gear ratio. This is a popular upgrade for many riders to get more power out of their quads. I will show the steps for changing both sprockets on an ATV, but for gear ratio purposes, you may only need to change one sprocket out. Check out my Complete Gear Ratio Guide if you need help with your gear ratio.
If you are changing a sprocket out for gearing reasons, I suggest changing the rear sprocket only if you can. If you are changing the sprocket due to wear and tear, I would suggest changing the chain out with it. It’s best for the chain and sprockets to wear together.
Luckily, changing a sprocket on an ATV is an easy job you can do at home. There are some specialty tools that can make the job easier, but I’ve been able to do this with regular everyday tools in my garage. Lets get started.
As always wear safety glasses and gloves when doing any type of maintenance on your machine. I find it helpful to spray the bolts and parts to remove with WD-40 or penetrating oil to make removal easier.
Step 1: Lift ATV And Remove Wheel
Now is a good time to loosen the nuts holding on the front and rear sprockets, if you’re changing them both out. I like to at least loosen them before I remove the chain because it makes it easier to take them off later. To keep the sprocket from rotating I stick a screw driver into one of the holes on the brake caliper.
If you don’t like the idea of using a screw driver through your brake caliper, they do make a Rotor And Sprocket Holder Tool found here on Amazon.
That keeps everything solid while you loosen the sprocket nuts. Also with the chain still on, the front sprocket won’t rotate either, making it easier to loosen those nuts as well. You could always have someone hold the rear brake down for you if you have a helping hand.
Step 2: Remove Rear Sprocket
If you’ve already loosed the nuts holding on the rear sprocket, this part will be easy. Just remove the nuts and you should be able to pull the rear sprocket right off. If it has gotten rusted on or is sticking, you may need to use a rubber mallet to persuade it loose.
Some people like to remove the chain before attempting to remove the rear sprocket, and that’s fine. I never have any problems removing the sprocket first, so that’s just how I’ve always done it. If you want to remove the chain first, scroll down to step , remove the chain, and then come back up here to continue.
Step 3: Remove Front Sprocket (Counter Shaft Sprocket)
If you’ve already remove the rear sprocket, it should be easy to take the chain off the front sprocket. You don’t need to remove the chain from the machine just yet. But freeing it from the front sprocket makes this step a lot easier.
If you’ve already loosened the bolts on the front sprocket, than this will be easy. Just remove the bolts holding the front sprocket on and remove the sprocket. Some ATVs will have a washer, security plate, or even a spring washer holding the sprocket in place.
If your new sprocket doesn’t come with washers or spring clips, take extra care with those parts because you will need to reuse the ones you have.
Step 4: Remove Master Link And Chain
If you look carefully along your chain, you will notice one of the links has a clip on the side. That’s the master link. You need to remove that clip before you can remove the master link. Once you have done that, the chain can be taken apart and taken off the machine.
You can remove the master link with a pair of needle nose pliers, a screw driver and hammer, or any other inventive way you can think. The usually pop right off pretty nicely. Sometimes they can be a bit stubborn, but they come off.
If your chain doesn’t have a master link, you will most likely want to get a Chain Breaker Kit Like This One from Amazon. You could use a rotary tool, a punch and a hammer, but I suggest just getting the kit. It’ll cost around 20 bucks and save you a world of headaches. You’ll need it if your new chain is too long anyway.
Step 5: Inspect Chain Slide And Rollers
Now that you’ve got both sprockets and the chain off the machine, it’s a good time to look at the chain slide and rollers to see if they need replacing. Usually these last a pretty long time, but can start to wear down. They help keep your chain under tension and are important for the operation of the ATV, so if they’re worn out, replace them.
They aren’t too expensive, so if you want to replace them, now’s the time to do it with everything apart. Here is a good set of Chain Roller Tensioner Wheel Guides from Amazon for a good price. They’re easy to remove and install, usually only one bolt to take off.
Step 6: Install New Front Sprocket
Usually when you order a new front sprocket, it comes with any security plates or washers and bolts that you need. If not, hopefully you saved your old ones. The install is pretty straight forward, just install the sprocket and then the security plate the same way you removed them.
Make sure you put the sprocket on the right way. Usually the side with numbers stamped on it (ex: 13T) will face outwards. That number indicates how many teeth the sprocket has.
I would also recommend putting thread lock on the bolts to make sure the sprocket doesn’t come loose while you’re riding. Medium strength thread lock should be fine. Anything stronger than that and you’ll have a rough time if you ever need to replace the sprocket again.
You will have a tough time getting the bolts tightened all the way down without a Rotor And Sprocket Holder Tool. If you don’t have that tool, just get them as tight as you can (hand tight) and you can finish tightening them down when you get the chain on.
Step 7: Install New Rear Sprocket
To install the rear sprocket, you’ll want to follow the same steps as you did with the front sprocket. Make sure the numbers are facing out, use thread lock, and tighten the bolts to hold it in place.
To tighten the bolts on the rear sprocket, you can put the screw driver in the caliper again. But this time in the top part to prevent the sprocket from rotating back when tightening, like you can see in the picture. It’s best to tighten the bolts in a criss cross pattern.
Step 8: Get Chain To Correct Length
If you’re looking for a new chain to replace your old one you’re going to need to know how many links you’ll need your chain to have. If you don’t feel like going out and counting all the links of your old chain, you could always just get the longest chain and cut it down for your quad.
Most chains come with 76, 90, or 110 links, so you’ll probably have to take some links out of whatever chain you get to fit your machine anyway. If you get a chain that is too short, you’ll have to add links with a rivet machine and it becomes a big headache.
Here’s a link to a Niche 520 ATV O-Ring Drive Chain from Amazon to help you start your search. I like the chains with the o-rings on every link, they seem to last longer and be better quality.
Once you have the new chain you can use the old one to size it up, like in this picture. I would still count the links to make sure you get the same size chain exactly. But laying the new chain next to the old one makes it easier to count.
There’s a number of ways to cut the chain to the right length, once you know which link you need to open. I’ve seen people use a rotary tool like a dremel to grind down the rivet on the link and pop it out with a punch tool.
But I suggest just getting a Chain Breaker Kit Like This One from Amazon. It just makes the job so much easier, mine has come in handy plenty of times now. And I no longer have nightmares about cutting chains with Fleetwood Mac ‘The Chain’ playing in the background.
Step 9: Install New Chain And Master Link
Now you have your chain to the right length, it’s time to install on the ATV. I would suggest starting the chain on the front sprocket and winding it through that way. It makes it easier to install the master link when the chain opening is near the rear sprocket.
Now insert the master link where the chain opening is, put the plate on, and put on the security clip holding the master link in place. You could use a pair of needle nose pliers or a screw driver to get the clip in place.
Don’t forget to tighten the front sprocket bolts down now if you haven’t already done so. Now with chain on and the back sprocket locked up, you should be able to tighten the front sprocket bolts all the way down tight.
Step 10: Adjust Chain Slack
The new sprockets are on, the chain is on, now you have to adjust the slack in the chain. You don’t want the chain to be too tight, it may break under the tension while you’re out riding. You don’t want too much slack in the chain either though.
The best way is to push down on the back of the quad and adjust the tension there, leaving about 1/4″ to 1/2″ slack in the chain. This way if you’re suspension bottoms out, it won’t break the chain because you have enough play to allow it.
I found a good method is to make sure you have 1/4″ to 1/2″ slack both up and down while you’re sitting on the ATV. That may cause you to be getting on and off the machine to make adjustments, but it’s always worked for me.
To adjust the slack in the chain, you’re going to have to loosen the bolts holding the rear axle and sprocket into place, as shown in the picture. Once those are loose, you should be able to adjust the tension bolts below them.
You will be able to tighten or loosen the tension bolts which will pull the back end of the ATV in or out. That’s how you adjust the tension in the chain. Make sure you keep an eye on the rear sprocket and chain and keep them in as straight a line as possible. I always try to adjust both left and right tension bolts the same amount to keep the sprocket from being crooked.
Once you have the chain to the tension you like, tighten the second nut on the tension bolt to keep it from moving, and tighten the bolts holding the rear end in place back down.
There you have it, new chain and sprockets. Now just get your tire back on and try it out. I would take it slow at first to make sure everything’s working ok.