If you’re a parent who’s ever let your kid hop on a 50cc Pit Bike for Kids and feel their excitement as they zoom around the yard, you know how rewarding a kid’s first pit bike experience can be. But after a few rides, you might notice something that’s easy to miss at first: a chain that’s too loose, too tight, or even coming off the sprocket mid-ride. I’ve spent years working with these bikes—helping kids and parents get the most out of their rides, and fixing small issues before they turn into big headaches—and adjusting a 50cc kids’ pit bike chain is one of the most important basic maintenance tasks you can learn. It’s simple, takes less than 15 minutes, and will keep your little rider safe and their bike running smoothly.
First, let’s talk why this matters so much for a 50cc model specifically. Kids’ pit bikes, especially Four Stroke Dirt Bike 50cc options (the most common type for young riders), are built for light, casual use—not heavy, off-road abuse. A misadjusted chain throws off power delivery, makes the bike harder to start, and increases the risk of it slipping or snapping while your kid is riding. And let’s be real: a loose chain that slaps against the frame can damage parts over time, while a tight chain puts extra stress on the engine’s sprocket and bearing, leading to premature wear.
Before you get started, gather your tools. You don’t need a fancy toolkit—just a few basic items: an adjustable wrench, a combination wrench set (most 50cc pit bikes use 10mm and 12mm wrenches for the axle and adjusters), a flathead screwdriver, and a tape measure. It’s also smart to set the bike on a flat, stable surface, or use a bike stand if you have one. If you don’t have a stand, flip the bike onto its side (make sure it’s on a soft surface like grass or a bike mat to protect the plastic body) so the rear wheel spins freely. That makes it way easier to check chain tension.
Now, let’s break down the step-by-step process, tailored specifically for 50cc kids’ pit bikes:
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Loosen the Rear Axle Nut
The rear of the bike has a long axle that holds the rear wheel in place. Find the axle nut (it’s usually on the right side of the bike; on some models, it’s on both sides, but the right side is where the adjusters are located) and use your wrench to loosen it. You don’t need to remove it completely—just turn it a few turns so the wheel can move forward or backward. This is key because adjusting the chain requires sliding the rear wheel to change the distance between the front and rear sprockets, which controls tension. -
Loosen the Chain Adjuster Bolts
On either side of the swingarm (the metal bar that the rear wheel attaches to), you’ll see two small bolts marked with lines or numbers (often 1, 2, 3 for alignment). These are the chain adjusters. Turn each adjuster bolt evenly (one full turn on the left, one full turn on the right) to loosen them. It’s critical to turn both sides the same amount—if you only adjust one side, the wheel will be out of alignment, which will make the chain wear unevenly and could cause it to come off. For example, if you turn the right adjuster ½ inch, turn the left adjuster ½ inch too. -
Check and Adjust Chain Tension
This is the most important step: measuring the slack in the chain. With your finger, push up on the middle of the chain (between the front and rear sprockets). On a 50cc kids’ pit bike, you want about 1 to 1.5 inches of vertical movement. That’s not too tight (you can barely push it) and not too loose (it wiggles more than 1.5 inches). If you’re not sure, a quick way to test is to grab the top of the chain and pull it away from the sprocket: it should move about an inch. For younger kids who ride gently, err on the side of a little more slack (1.25 inches) rather than less—stiffer riding can cause the chain to stretch, so a tiny bit of extra slack prevents snapping during a backyard ride. -
Align the Rear Wheel
Once you have the right tension, double-check that the rear wheel is straight. Look at the adjuster marks on both sides of the swingarm—they should match exactly. If the left adjuster is at mark 2, the right adjuster should also be at mark 2. If they’re even, the wheel is aligned. If not, make small adjustments to both sides until the lines line up. A misaligned wheel causes uneven tire wear and makes the bike hard to steer, which is a safety risk for kids learning to ride. -
Tighten Everything Back Up
When you’re happy with tension and alignment, hold the rear wheel in place (so it doesn’t slide forward or backward) and tighten the chain adjuster bolts first. Again, do this evenly, one side at a time. Then, tighten the rear axle nut to manufacturer specifications (usually around 25 to 30 foot-pounds—if you don’t have a torque wrench, tighten it until it’s snug, and give it a little extra turn, but don’t overdo it). Once everything is tight, spin the rear wheel a few times to make sure the chain moves smoothly without rubbing against the frame or the swingarm. If it catches, double-check your alignment or tension—you may have adjusted too tight.
A few quick pro tips from working with these bikes every day: First, check your chain tension before every ride, especially if your kid has been riding on dirt or grass. Dirt can get into the chain and cause wear, and constant small bumps can stretch it slightly. Second, lubricate the chain every 5 to 6 rides with a chain-specific lubricant—this prevents rust and makes the chain last longer. You can find chain lubricant that’s safe for all Pit Bike Mini Cross Motorcycle 110cc and 50cc models, so you don’t have to worry about buying something incompatible.
It’s also worth mentioning that 50cc pit bikes are often a kid’s first bike, so ease of maintenance is key. Unlike larger models, which might require more complex adjustments, these small bikes are designed for parents to work on at home without a lot of experience. If you’re looking for a new bike for your kid, our line of 50cc Pit Bike for Kids includes the reliable Four Stroke Dirt Bike 50cc model, perfect for beginners learning to handle a pit bike. We also carry options like the Four Stroke 125cc Dirt Bike 110cc Air Cooled Pit Bike as kids grow, and the easy-to-use 110cc Automatic Pit Dirt Bike for even younger riders who don’t want to deal with a clutch.
If you have questions about adjusting your chain, or want to learn more about our line of kids’ pit bikes, don’t hesitate to reach out to our team to discuss your needs. Whether you’re a first-time pit bike owner or looking to upgrade your kid’s ride, we’re here to help you find the right fit and keep your little rider safe on every adventure.
References:
- Pit Bike Maintenance: Chain Adjustment Guide for Small Displacement Models
- Kids’ Dirt Bike Safety and Maintenance Best Practices
- Four Stroke Engine Care for 50cc and 110cc Pit Bikes
