Here’s something I never admitted before…
I find the mechanics of a motorcycle fascinating! Even more than that of a car.
And one simple thing that’s an integral part of a motorcycle is the drive chain.
To make your ride smooth and safe, the tension in the chain needs to hit the sweet spot. If you have a loose chain, you will surely run into serious trouble.
That means you need to recognize the symptoms of a loose motorcycle chain and take the right preventive measures.
Without much ado, let’s start the journey. There’s a lot to discuss.
What’s the Function of a Motorcycle Chain?
Chains have been used for centuries to transmit power and act as a drive mechanism.
Think of the bicycle you rode as a kid.
If you don’t know this, the first sketches of steel chains were made by Leonardo da Vinci in the 16th century. (Did I ever tell you how much I love a good history lesson?)
Ever wondered why chain systems are so popular?
Firstly, they are inexpensive and easy to make. Next, they are extremely efficient and transfer the maximum power without loss.
On the downside, they are messy and need a lot of maintenance.
No more sidetracking. Let’s come back to motorcycle chains.
There are two sprockets in a motorcycle that act as the seat of power. The front sprocket is connected with the engine output shaft and the rear sprocket is mounted on the rear wheel.
Both sprockets have a fixed number of teeth that connect with the gaps in the drive chain. As the front or the drive sprocket rotates with the engine shaft, the chain transmits power to the rear or the driven sprocket. As a result, power is transmitted to the rear wheel.
All chain link mechanisms have multiple components like the outer plate, inner plate, pin, bushing, and rollers. The two main types of chains in the market are O-ring or X-ring chains. These come with a seal between the locking pins that retain the lubrication.
What’s the difference?
Basically, the cross-sections of the rubber seals are different. It’s O-shaped for the former and X-shaped for the latter.
The bottom line is this…
X-ring chains reduce drag and friction and last longer.
Keep in mind that motorcycle chains aren’t interchangeable. Each motorcycle type has a specific chain that matches the sprocket design.
Now that you understand the importance of the chain in a bike, let’s look into the subject of loose chains.
Why Do Motorcycle Chains Get Loose?
So, your motorcycle chain gets loose over and over again, in spite of your best efforts.
We’ve all been there. (On a philosophical note- the road to smooth rides is paved with uncertainties.)
Here are some main reasons behind a loose chain.
- In new motorcycles, there can be some amount of slack between the chain links. That will reduce as the chain elements gradually wear out. You will need to tighten it if needed.
- The chain adjustment bolt on either side of the rear wheel can get loose or damaged. That can result in a loose chain.
- The threads on the rear axle or the connecting nuts might get worn out.
- In case the chain sprocket is damaged, or worn out, the chain will get loose even after you tighten it.
- Elements like rust and dirt inside the chain can also be another cause. You need to examine the chain and replace it if needed.
What happens when your motorcycle chain is loose?
- A loose chain might not mesh perfectly with the sprocket and slide over the sprocket tooth. That will affect power transmission and can cause the motorcycle to oscillate.
- A loose chain creates jarring noises and can even move out of the sprocket entirely. Needless to say, this is dangerous for the rider. Think of losing power in your rear wheel in the middle of a freeway.
- Due to the uneven power transmission, the wheel movements can become jerky.
- With a loose chain, the rollers and rubber seals inside the chain will wear out quickly.
Does that mean you should tighten the chain with all your Jedi powers?
Every motorcycle needs a precise amount of chain tension that’s mentioned in the owner’s manual. You might also find them on a sticker on the swing arm.
If you tighten the chain too much, it can result in excess wear and tear and even chain breakage. The higher friction will result in more power loss and you can even lose control around tight corners. Also, the handling of the bike will be affected due to a tight chain.
What Are Loose Motorcycle Chain Symptoms?
The good news is, a loose chain isn’t an issue that will catch you totally unaware. There are some obvious signs that will come to your notice.
Time to pay attention. (Don’t tell me. My attention span is as good as that of the average goldfish)
1. A low hanging chain
The most obvious sign of a loose chain is the chain hanging low. I have seen seasoned riders tell it by taking one look at the chain.
If you think that’s the case, measure and adjust the chain. Check the instructions in the owner’s manual for details. Ideally, the lowest point of the chain is at the midpoint of the two sprockets.
Frankly, adjusting the chain is a simple task. All you need to do is tighten the axle nut as per the torque specified in the owner’s manual.
Does measuring lengths and performing brain-jarring calculations give you a headache worse than a hangover?
Then you can check out some tools that can be used to measure chain slack.
And I have said this already, haven’t I? Better consider them as holy words carved in stone.
A too-tight chain is as bad as a loose one.
2. A chain tug
This happens when you are riding steady at lower gears. Generally, the drive chain is the loosest while running in the lower gears. If it’s already loose, the excessive slack will create a reverse force that will pull against the clutch. In some cases, it might feel like the loss of transmission.
Basically, the loose chain resists the forward momentum of the bike.
3. A jerky feeling
With a loose chain, there can be a jerky feeling when you speed up the motorcycle. This will be accompanied by a lashing sound.
If you continue to ride the bike at this point, the chain will get dislodged from the socket. In that case, the bike is most likely to stop. In some cases, there will be a slapping sound as the chain hits the swindle arm.
Note, this is a late symptom that can be dangerous. It’s best to fix a loose chain before this happens.
4. Clanky noise
A loose chain can make clanking or grating noises as it connects loosely with the sprocket teeth. Also, with too much slack, the chain will make excessive up and down movement. This can also be a reason for a rattling noise.
Keep in mind, improper tension in the chain can also give rise to noise. Other reasons for noise can be a worn-out chain or sprocket, or a loose sprocket nut.
Granted, these are noisy times we live in. But don’t let that make you overlook the noise coming out of the motorcycle chain. Especially if it reaches your ears while riding.
5. A worn-out chain
If your drive chain is as old as the spear of Odin, chances are it will get loose frequently. A quick visual inspection might tell you that a few rollers are missing or the O-rings have worn out.
Here’s an easy way to check.
Try pulling out the chain from the rear sprocket. A chain in good condition won’t move out and fit snugly around the sprocket teeth. But a worn-out chain will reveal a major portion of a socket tooth.
That means you need to install a new chain.
And remember: a new chain won’t fit snugly over a worn-out socket and there will be more noise. It’s best to replace the chains and sprocket together.
How to Prevent Motorcycle Chain Loose Symptoms?
Ideally, you need to prevent the chain from loosening before the symptoms start. The rule of thumb is to inspect your chain every 500 miles.
For any chain-driven motorcycle, proper maintenance of the chains by periodic cleaning and lubricating is a must. Lubricate the chain every 4,000 to 5,000 miles or six months and perform regular maintenance.
If you’re riding an old bike, I would suggest that you inspect the chain regularly. In case the chain or sprocket is worn out, replace them. Even if a few teeth are worn out, the ripple effect can quickly wear out the remaining teeth. If needed, you need to replace the rear axle too.
Frequently Asked Questions
How do you know if your motorbike chain is loose?
You can visually inspect a chain to find out if it’s hanging too low. Besides, there can be chain tug while running at lower gears. Other symptoms include a jerky feeling or a noise from the chain.
How do you fix a loose motorcycle chain?
There are adjusters on both sides of the rear wheel that can be used to shift the axle position and adjust the chain slack. Make sure that the adjustments are the same on both sides. Then check the chain slack against the manufacturer’s specifications.
Does a loose chain cause vibration?
Usually, a loose chain doesn’t lead to vibrations. Vibrations may be caused by uneven treads, unbalanced tires, loosened engine mount bolts, or a cracked suspension. However, if a chain is too tight, it might increase the load on the engine and cause vibrations.