Let’s be honest, staring at a worn-out chain on your kid’s Polaris Outlaw 90 can bring up a dozen questions. Is it a #420 or a #428? How many links do I need? If I change the sprockets, does the chain length change? It’s a common headache for even seasoned DIY mechanics, and getting it wrong can lead to poor performance or, worse, a dangerous failure on the trail.
You can stop the guesswork right now. This is your definitive guide, packed with expert polaris outlaw 90 chain size tips straight from the FatBoysOffroad garage. We promise to demystify chain sizes, tension, and replacement so you can wrench with confidence.
In this article, we’ll break down exactly what the stock chain size is, how to decode those confusing numbers stamped on the side plates, and provide a step-by-step guide to measuring, replacing, and adjusting your chain for maximum safety and fun.
What is the Stock Polaris Outlaw 90 Chain Size?
Let’s get straight to the most important piece of information. The factory-spec, stock chain for a Polaris Outlaw 90 is a #420 chain with 74 links.
Write that down, save it in your phone, or tattoo it on your toolbox. Knowing this simple fact is the foundation for all your chain maintenance. This size is specifically matched to the stock front and rear sprockets that came on your youth ATV from the factory.
If you’re just doing a simple replacement and haven’t changed your sprockets, buying a #420 chain and cutting it to 74 links (or buying a pre-cut 74-link chain) is your fastest path back to the trails. But what do those numbers actually mean? Understanding this is key to making smart upgrade decisions down the road.
Decoding Chain Numbers: What Do #420, #428, and #520 Really Mean?
Chain sizes aren’t random; they’re a standardized system. Knowing how to read them unlocks a deeper understanding of your machine. This knowledge is central to any good polaris outlaw 90 chain size tips guide.
Understanding Chain Pitch
The first digit in a chain size (the “4” in #420) tells you the pitch. Pitch is the distance from the center of one pin to the center of the next pin. The system is based on 1/8th of an inch.
- 4xx Series Chain: The “4” means the pitch is 4/8″, which simplifies to 1/2″.
- 5xx Series Chain: A “5” (like on a #520 chain) means the pitch is 5/8″.
You must always match the chain pitch to your sprockets. A #420 chain will not work on #520 sprockets, and vice-versa. They simply won’t mesh.
Roller Width and Diameter
The last two digits (the “20” in #420) refer to the chain’s roller width and diameter. While the specifics are highly technical, the important takeaway is that “20” represents a standard size. A #428 chain, for example, has the same 1/2″ pitch as a #420, but its inner plates are wider and the rollers are thicker, making it a beefier chain.
Why You Might (or Might Not) Upgrade to a #428 Chain
Some riders consider “upgrading” the Outlaw 90’s drivetrain to a #428 chain and sprocket set. There are some benefits of polaris outlaw 90 chain size tips like this, but also drawbacks.
- Pros: A #428 chain is stronger and more durable. It can handle more abuse and may last longer, especially in very muddy or sandy conditions.
- Cons: It’s heavier. This extra rotating mass can rob a small amount of power from the little 90cc engine. Crucially, you must change both sprockets and the chain together as a matched set.
For most riders, the stock #420 setup is perfectly adequate and the most cost-effective solution.
Your Complete Polaris Outlaw 90 Chain Size Tips Guide
Getting your chain replacement right involves more than just buying the right box off the shelf. Here are the essential tips and techniques to ensure a perfect fit every time.
How to Accurately Count Your Chain Links
If you’re unsure if your current chain is the stock length, counting the links is easy. Don’t count the outer plates or the inner rollers—count the pins that hold it all together.
The easiest way is to find the master link. Start at the pin right next to it, mark it with a paint pen or zip tie, and count every single pin as you go around until you get back to your starting point. For a stock Outlaw 90, you should count 74 pins.
Measuring for a New Chain (Especially with Aftermarket Sprockets)
Did you change your sprocket sizes for more low-end torque or top-end speed? If so, the stock 74-link length is no longer valid. You’ll need to measure for a new custom length.
Install your new sprockets on the ATV.
Slide the rear axle almost all the way forward in the swingarm adjustment slots. This gives you maximum room to tighten the chain later as it stretches.
Wrap your new, uncut chain around both sprockets. Pull it snug along the top run.
Find the closest spot where an outer and inner link can be joined with a master link. This is your cut point. Use a high-quality chain breaker tool to press out the pin at your marked spot.
Choosing the Right Type of Chain: Standard vs. O-Ring
You’ll also see options for “standard” non-sealed chains and “sealed” O-ring or X-ring chains.
- Standard Chain: This is the most common and affordable type. It’s what the Outlaw 90 comes with from the factory. It works great but requires more frequent cleaning and lubrication.
- O-Ring/X-Ring Chain: These have tiny rubber seals (O-rings or X-rings) between the plates that trap grease inside the pins and rollers. They last much longer and require less maintenance, but they cost more and create slightly more drag.
For an Outlaw 90, a quality standard chain is usually sufficient. However, if you ride in a lot of water and mud, an O-ring chain is a fantastic, long-lasting upgrade.
Common Problems with Polaris Outlaw 90 Chain Size and Tension
Incorrect sizing and poor adjustment are the root of most drivetrain failures. Understanding these common problems with polaris outlaw 90 chain size tips will save you money and prevent a breakdown.
The Dangers of a Chain That’s Too Loose
A loose chain is a noisy and dangerous chain. You’ll hear it slapping against the swingarm. The real risk is derailment. If the chain jumps off the sprockets at speed, it can lock the rear wheels, break the engine case, or cause a crash. Always check your tension.
The Hidden Damage of a Chain That’s Too Tight
A chain that’s too tight is just as bad, if not worse. It puts immense stress on the front sprocket’s output shaft bearing, the wheel bearings, and the chain itself. This silent killer causes accelerated, expensive wear on parts you can’t easily see.
Spotting a Worn-Out Chain and Sprockets
Look for these tell-tale signs of a tired drivetrain:
- “Shark Fin” Sprockets: The teeth on the sprockets should be symmetrical. If they are hooked or pointed like a shark’s fin, they are worn out.
- Stiff Links: As you rotate the chain, watch for links that stay kinked or don’t straighten out smoothly.
- Chain Stretch: Try to pull the chain away from the back of the rear sprocket. If you can pull it back more than half a tooth, the chain is stretched and needs replacement.
Pro Tip: Always replace your chain and both sprockets as a complete set. Putting a new chain on old, worn sprockets will destroy the new chain in a matter of hours.
Step-by-Step: How to Replace and Adjust Your Outlaw 90 Chain
Ready to get your hands dirty? Follow these steps for a perfect installation. This is how to polaris outlaw 90 chain size tips are put into action.
Tools You’ll Need
- Socket and Wrench Set
- Chain Breaker Tool
- Master Link Pliers (optional, but helpful)
- Tape Measure or Ruler
- Chain Lube and Cleaner
Removing the Old Chain
Safely support the rear of the ATV on a stand so the rear wheels can spin freely.
Loosen the bolts on the rear axle carrier so it can slide forward and backward.
Find the master link on your old chain. It has a removable clip on one side.
Use pliers to slide the clip off, then remove the side plate. The chain should now come apart.
Installing the New Chain
Route your new chain (cut to the correct length) around the front and rear sprockets.
Bring the two ends together and install the master link from the backside, so the pins are pointing out towards you.
Place the side plate over the pins, then install the clip. Crucially, the closed end of the clip must face the direction of chain travel. This prevents it from being snagged and flying off.
Setting the Perfect Tension
Proper tension is critical. The owner’s manual specifies about 1/2 to 3/4 inch of total up-and-down slack. Find the midpoint of the chain on the bottom run.
Push down on the chain and then pull up. The total distance it travels should be within that range. Adjust the chain by sliding the axle carrier back to tighten or forward to loosen. Once the tension is perfect, make sure the axle is straight by measuring the distance from the swingarm pivot to the axle on both sides, then tighten the carrier bolts to spec.
The Polaris Outlaw 90 Chain Size Tips Care Guide for Longevity
A new chain and sprockets are an investment. Follow this polaris outlaw 90 chain size tips care guide to make them last as long as possible.
Best Practices for Cleaning Your Chain
A clean chain is a happy chain. After a muddy or dusty ride, use a grunge brush and a dedicated chain cleaner (or kerosene) to scrub away all the grit. Avoid using harsh solvents like brake cleaner, as they can damage the seals on an O-ring chain.
The Right Way to Lubricate
Always lubricate a clean, warm chain (ideally, after a short ride). Apply a quality motorcycle or ATV chain lube to the inside of the chain run, so centrifugal force drives the lube into the rollers. Let it sit for a few minutes to set up, then wipe off any excess with a rag to prevent it from flinging everywhere.
Sustainable and Eco-Friendly Chain Maintenance
Practicing smart maintenance is also good for the planet. These are the sustainable polaris outlaw 90 chain size tips you can feel good about.
- Reduce Waste: Following proper cleaning and lubrication best practices drastically increases the life of your chain and sprockets. This means you buy fewer parts over the life of the ATV, reducing manufacturing demand and waste.
- Choose Greener Products: Look for high-quality, biodegradable chain lubes. These products work exceptionally well and are formulated to break down naturally, minimizing their impact on the trails and environment.
- Prevent Pollution: A well-lubricated chain that has the excess wiped off flings less oil and grime into the ecosystem. It’s a small step that makes a big difference.
Frequently Asked Questions About Polaris Outlaw 90 Chain Size Tips
How often should I replace the chain on a Polaris Outlaw 90?
There’s no set hour or mile interval. It depends entirely on riding conditions and maintenance. Inspect the chain for wear and check the tension before every ride. For an average rider who keeps it clean and lubed, a quality chain and sprocket set can last several seasons.
Can I use a chain from another ATV on my Outlaw 90?
You can, but only if it’s the correct pitch (#420) and you cut it to the correct length (74 links for a stock setup). It’s always safer and easier to buy a chain specifically marketed for your machine to ensure compatibility and quality.
What’s the difference between a clip-style and a rivet-style master link?
A clip-style link uses a removable clip for easy installation and removal, which is perfect for the lower-power Outlaw 90. A rivet-style link requires a special tool to flare the pins for a permanent, stronger connection, typically used on high-power street bikes and race machines.
Do I really need a chain breaker tool?
While you can use an angle grinder in a pinch, it’s messy and risky. A chain breaker tool is the right way to do the job. It cleanly and safely presses the pin out, allowing you to easily size a new chain or remove an old one without a master link. It’s a worthy investment for any DIY mechanic.
Mastering your Polaris Outlaw 90’s chain isn’t just about maintenance; it’s about ensuring safety, reliability, and performance every time your young rider hits the throttle. By understanding the stock size, how to properly adjust tension, and when to replace worn parts, you’re taking control of your machine’s health.
Keep this guide handy, inspect your chain before every adventure, and don’t be afraid to get your hands dirty. Now you’ve got the knowledge to do the job right. Wrench with confidence, and ride safe!
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