What Causes Motorcycle Chain Slap

What causes motorcycle chain slap? If you’re lucky, it’s the chain that is too loose. But in severe cases, you could be looking at a full chain and sprocket replacement.

But before we dig into all of that, what even is chain slap? If you’ve noticed your chain swinging up and down every time you counter a harsh obstacle, that’s chain slap.

Chain slap can happen for many reasons, mostly due to low tension in the chain. However, lack of maintenance and lubrication can also lead to a worn-down chain that stretches and deforms.

While it’s quite common, chain slap is not the only noise your chain makes. A constant clunking sound is likely the cause of a worn chain or sprocket.

So, how do you go about fixing that? Fortunately, you can fix the issue with simple chain adjustments and tightening some bolts. If the situation is too severe, however, you’ll need to make some replacements.

What’s A Motorcycle Chain Slap?

What's A Motorcycle Chain Slap

Chain slap is a faint sound produced by your chain as it “slaps” up and down whenever your bike rattles. The noise is more prominent when going downhill.

Some bikes may already come with chainstay protectors. But even with those, you may experience chain slap as they’re mainly designed to guard the frame beneath the chain.

But that doesn’t mean chainstay protectors aren’t instrumental in keeping chain slap at bay. With the right tools and a little modification, you can combat chain slap. The best part is that fixing a chain slap doesn’t even require a lot of work. With a little help from the user manual, you can DIY the whole task.

What Causes Motorcycle Chain Slap?

Cause of a Motorcycle Chain Slap

Before we begin, we must discuss what causes motorcycle chain slap. Several reasons cause chain slap. The most common cause of motorcycle chain slap is that your bike is running on the stand. This leaves the chain hanging freely, causing it to slap aggressively. But this issue should be fixed as soon as you start riding the bike.

If not, then you have a deeper problem. The primary cause of chain slap is improper tension in the chain, allowing it to sway up and down. You must adjust the tension in the chain to the right amount.

But is it a chain slap that you’re hearing? More often than not, you might think chain slap is just the parts of the chain clunking against each other. You may need better lubrication in this case.

Is It Normal for A Motorcycle Chain to Make Noise?

Chain noises are normal as the chain is a moving component of the bike. However, if your chain makes rattling, clicking, or slapping sounds, you shouldn’t ignore it.

A loose chain causes slapping sounds in particular. And loose chains can present a whole spectrum of problems. They may interfere with gear shifting. And if the chain is too loose, it may come completely off.

Similarly, rattling noises often indicate that your chain is wearing down and that there isn’t enough lubricant. This will hinder the normal operation of the chain and hence the whole bike.

The chain’s tension also causes clicking noises, much like chain slap. Luckily, you can fix the motorcycle chain problem using nothing but home remedies and consultation from the user manual.

Top 8 Reasons for Motorcycle Chain Noise:

So, what causes motorcycle chain slap? Here are a few possible reasons:

1.    Running on The Stand:

Running motorcycle on The Stand

If you notice chain slapping only when your bike is stationary, it could be because your motorbike is on the stand. This is because when your bike is running on the stand, the rear wheel is free to float in the air. This leaves the tension on the chain loose, resulting in a chain slap.

So, what should you do in this case? Nothing. A chain slap when running on the stand is normal in many situations and nothing to worry about. Just make sure you don’t hear the sound during your ride.

2.    Improper Tension:

Improper chain tension is what causes chain slap. But you can start by directly adjusting the chain’s tension without looking at any other component.

For this, you’ll need to consult your bike’s manual to find out the right tension and how to adjust the tension on the chain.

3.    Chain Hits the Sprocket Cover:

Motorcycle Chain Hit the Sprocket

Sometimes, the chain slap sound isn’t really from the chain slapping. Your chain could be hitting the sprocket cover or the chain guard during its operation. This will also create a sound similar to chain slap.

Hitting the sprocket cover or chain guard may produce momentum that can cause an actual chain slap.

The best way to fix this is to realign your chain, sprocket cover, or chain guard or replace the culprit entirely.

4.    A Loose Nut in The Sprocket:

A loosened nut in the front sprocket could also be the culprit. Loose nuts will lead to the chain slapping against the sprocket since the sprocket is not in a stable position. This will also cause other noises. And you’ll most likely be able to track it down to the front sprocket.

Unfasten the bolts holding the sprocket cover and take a look inside. Move the front sprocket side by side and see if it budges.

5.    Worn-Out Chain:

Worn-Out motorcycle Chain

Worn-out chains may also cause chain slap. When the chain wears out, it loses its tension. The formation of rust and other corrosive substances are to blame for this.

Rust on the chain will weigh it down, causing more slap. And if it’s too severe, it can even break. Remove the rust if possible, or replace the chain entirely.

6.    Worn-Out Sprocket:

Just like the chain, the sprocket can also wear out and hit the chain. Check the sprocket for any obvious signs of wear. But do be wary of lesser-obvious signs. Check for any rust formation. Remove any rust on the sprocket using any rust-removal solution.

7.    Needs More Lubrication:

Chain slap can be easily mistaken for grinding clunking sounds in the chain. That’s not a chain slap. That’s just wear and lack of lubrication. Even if you don’t think it’s that, try lubricating the chain. You’ll immediately notice a difference in the “slap.”

8.    It’s Not the Chain:

Finally, if everything seems to be pitch-perfect, then it’s not the chain. Your bike has thousands of moving parts. So, it’s no surprise that any one of them could be the culprit. The output shaft is the most common cause of noise coming from what appears to be the chain.

How Do You Stop Motorcycle Chain from Making Noises?                  

How to stop motorcycle chain noise

Now that you know what causes it, how do you fix chain slap? Each problem requires its solution. Here’s what you can do to stop your chain from making noises:

  • The first step is to check the tension of the chain. Adjust the tension according to what is mentioned in the user manual. If you’ve recently made adjustments to the chain and the chain is starting to slap, then you know the tension is the problem.
  • Next, clean the chain of any dirt and grime. Apply any appropriate rust-removing solution. You may need a chain cleaning brush to get in between the crevices. Or remove the chain entirely to clean it.
  • Then, lubricate the chain to prevent rattling. Also, lubricate the sprocket.
  • Tighten the nuts and bolts of both the front and rear sprockets if they seem loose.
  • If the chain or the sprocket are too worn out, replace them.
  • Ensure that the chain isn’t hitting the cover of the sprocket or the chain guard.
  • Take a look at the transmission and primary chains and try to spot malformations or anything that could malfunction.
  • Finally, if all else fails, let a professional have a look.

FAQ

What happens if the motorcycle chain is loose?

If the chain is too loose, it can jump from one gear to the next, and in extreme cases, it may come off. A loose chain will also create a slapping noise, which can be agitating at times.

How do you silence a chain slap?

The easiest way to silence a chain slap is to adjust the tension in the chain. You can also lubricate the parts and tighten any loose nuts or bolts on the sprockets.

Do motorcycle chains stretch?

Yes, the plate holes and bushes between the chains can stretch due to wear. Other forms of wear in different places can lead to stretching and the fact that metal is elastic, much like any other material.

How often should you tighten the motorcycle chain?

It is recommended to inspect your chain and tighten it if it’s too loose every 805 km (500 miles). You should do so more frequently if you have a dirt bike.

How often should I lube my motorcycle chain?

You should lube your motorcycle chain about every 300 to 600 miles or so. Lubrication is key to healthy chain operation.

Conclusion

Motorcycle chain slapping can be quite a nuisance. But chain noises tell you a lot more about your bike and its health.

What causes motorcycle chain slap? Anything from loose tension to lack of lubrication and even the chain hitting the sprocket cover can cause a chain slap.

Luckily, you can fix the issue by simply adjusting the tension on the chain or lubricating it. Each issue requires its solution. But it’s nothing you can’t do at home.

And if all else fails, you can always go to a professional. They’ll know how to fix that noisy chain!

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