A grinding sound can be one of the most annoying and worrying sounds a motorcycle can make.
If your bike is affected by this issue, you’ve come to the right place…
We’ve put together a complete guide of common causes and their solutions behind motorcycle grinding sounds.
Table of Contents
Motorcycle Grinding Noise When Starting
The most likely reason your motorcycle makes a grinding sound at startup is a defective or worn-out starter. Starter malfunctions that cause grinding include broken gear teeth, a worn solenoid, or inadequate alignment between the starter and the flywheel’s ring gear.
If a faulty ring gear is why the alignment between the starter and flywheel is off and, therefore, grinding at startup, the ring gear will have to be replaced.
In all the other scenarios mentioned above, replacing the starter unit is the only way to make the grinding stop.
A faulty starter is often overlooked as the cause of grinding when pushing the motorcycle’s starter button since a failing starter may still have the torque it needs to spin the flywheel and start the bike’s engine.
All motorcycle starters wear out eventually, and that process of wearing out is gradual.
The starter will get weaker and weaker, coughing and grinding but still starting the engine.
That said, a starter that makes grinding noises is on the verge of expiration; failing to replace a grinding starter can eventually leave you stranded.
Repairing any starter’s components isn’t economical, as replacing the whole starter is inexpensive and straightforward for any capable mechanic.
If the flywheel gear is the reason your bike makes grinding noises, replacing the flywheel is a technical task best left to experienced mechanics.
Motorcycle Grinding Noise When Slowing Down
The most common reason a motorcycle makes a grinding noise when slowing down is because of a worn chain and sprockets, expired brake pads, or a dry, corroded, or damaged clutch.
If your motorcycle’s chain is worn and corroded, it will lock up during deceleration, grinding against itself and the sprockets.
If the sprockets that roll the chain are corrupted, damaged, or unaligned, you’ll hear the same chunky, metal-on-metal sound.
- In some cases, the condition of the chain and sprockets are fine, but the chain slack isn’t adjusted to spec.
- An over-tightened chain will make intrusive metallic noises while you’re slowing the bike and, therefore, the chain’s momentum.
- The specific slack measurement varies from make and model; you can find the spec for your chain tension in the owner’s manual associated with your make and year model motorcycle.
- Finally, if your motorcycle’s chain lacks lubrication, it will make some grinding noises even if it’s adjusted to spec and in good condition.
- Chain lubrication is part of routine maintenance but should also be done after every long ride in harsh weather conditions.
The chain is likely the source of the grinding noise if the sound happens, regardless of whether you’re slowing down with your front and rear brakes or by engine braking with the clutch lever.
Conversely, if the grinding sound only happens with one of these stopping methods and not the other, we can assume that is where the grinding noise is coming from.
Worn or compromised brake pads are the next place to look if your motorcycle makes a grinding noise only when applying your brakes. If the grinding noise happens when you disengage the clutch lever to the engine brake but not when you touch the brakes and leave the clutch engaged, the clutch or something else in your gearbox is causing it.
Here are a few other reasons a motorcycle makes abrasive metallic sounds when slowing down:
- Worn output shaft bearings
- Loose Transmission Pully Nut
- Faulty Wheel Bearings
Note: Do not ride your motorcycle if you suspect any of these are the culprits behind your motorcycle making grinding noises when decelerating.
Motorcycle Grinding Noise When Accelerating
If your motorcycle’s engine or gearbox makes a grinding noise while accelerating or in motion, the issue could be faulty bearings. Bearing failure is a severe issue that can cause engine damage, control loss, collision, or death and should be diagnosed and repaired before riding.
As soon as you suspect worn, faulty, or corroded internal bearings on a motorcycle, it’s time to pull over and at least confirm bearing failure isn’t the problem before you continue to ride.
If it’s not a grinding bearing in your engine or gearbox, it might come from the wheel bearings.
Still, if your motorcycle’s wheel bearings are making any noise, it could be because of a pending failure, which will lock up your wheels and cause a collision.
- On a shaft-driven motorcycle, a grinding noise while in motion might be caused by a rear-drive gear spline that lacks lubrication.
- you can fix the spline lubrication issue in this less drastic situation with a quick grease application.
- If left unchecked, however, you risk excessive wear and tear on the drive gear, which can cause more significant problems down the road.
Your idle adjustment could be off, causing the throttle to overwork on acceleration.
Finally, a crack or leak in your air intake manifold can cause a vac leak that causes strange motorcycle sounds during acceleration.
Motorcycle Grinding Noise When Releasing the Clutch Lever
A motorcycle that makes grinding noises while releasing the clutch has an issue with its transmission. It could be as simple as a low-oil level situation where the clutch grinds due to a lack of lubrication. Grinding can be caused by contaminated oil or improper oil levels or damage to the gearbox.
If you’re noticing the grinding metal sound when your bike is in neutral, and you let the clutch lever out, and the noise goes away when your pull the clutch lever in, the sound likely has nothing to do with the engine or starter and is somewhere in your transmission:
- Worn or poorly adjusted Clutch Cable
- Chipped Gears
- Corrosion on Clutch
- Debris in Oil
- Debris in Gearbox
- Loose Clutch Plates
- Faulty Clutch Basket
- Damaged Throw-Out Bearing
Motorcycle Grinding Noise When Shifting Gears
Motorcycles make grinding noises while shifting gears when the clutch basket fingers are worn or damaged by the clutch disc’s motion. Other common reasons motorcycles make grinding sounds when shifting are worn shifting forks, a bent shifting shaft, worn gear teeth, damaged gears, or a worn and poorly adjusted clutch cable.
Groove-damaged clutch basket fingers are particularly common on hard-ridden, older bikes or on dirt bikes and sportbikes, on which riders tend to be trigger-happy on the throttle.
As you open and close your throttle while riding, the clutch discs tend to knock into your clutch basket.
While the damage is nominal at first, in time, or if the bike is pushed hard, this knocking motion cuts notches into the clutch basket fingers.
This problem can be exacerbated by a slew of maintenance factors, like oil levels and condition and frequency of service, as well as riding habits.
If the clutch isn’t inspected regularly, these notches can get worse and worse and go undetected until they get deep enough to get stuck.
The groove damage hinders the clutch basket fingers’ release motion, meaning they fail to fully disengage the clutch when you pull your clutch lever, causing a grinding sound to come from your transmission when you shift gears.
- If the grooves worn into your clutch basket fingers are less than 1 millimeter deep, you can temporarily solve the grinding noise problem on your motorcycle by filing down the grooves.
- That said, this compromises the fingers and makes them more susceptible to damage as the reduction in distance from the filing gives the clutch discs more knocking momentum as they continue to wear down the fingers.
- Eventually, the clutch basket fingers can crack and snap off, making it imperative to change the damaged clutch basket either as soon as you discover the grooves.
- If you use the temporary fix mentioned above, know that it’s only meant to get you where you need to go without grinding your gears and causing more damage. We suggest you take it to a mechanic shortly after you file down the fingers and have a new clutch basket installed.
On a long enough timeline, all machine parts wear, hence the notches worn into the basket fingers from typical use. Still, the slight damage can prevent the fingers from spreading apart to fully disengage the clutch, causing a grinding noise when you’re shifting gears.
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Motorcycle Starter Grinding Noise
Motorcycle starters make grinding noises when the solenoid isn’t magnetizing or if teeth on either gear snap off, bend, incur rust or fail to align for any reason. It indicates a starter problem that could get worse at every attempt.
To understand how this can happen, let’s examine how a motorcycle starter works:
- A modern motorcycle starter is an electrically powered motor, juiced by your bike battery, that activates the flywheel and spins the crankshaft that causes all the primary engine functions.
- The battery sends a charge through the starter relay to the solenoid, a magnetic device that then engages a small gear on the starter. The gear grips the flywheel’s ring gear and turns it.
- Once the flywheel is in motion, the starter gear and the flywheel gear disengage.
Fixing a starter piece by piece is a waste of time and money, as replacing the entire starter unit is cheap and simple for any decent wrencher.
However, if the flywheel gear is the grinding source, you’ll have to uninstall the flywheel, a complex job left for an experienced pro.
Motorcycle Chain Grinding Noise
If your motorcycle is chain driven, your final drive will make grinding noises because your chain is rusted, lacks lubrication, your chain and sprockets are unaligned, chain tension is out of adjustment, or your chain links are kinked up.
Final chain drive grinding can happen intermittently or constantly, depending on the cause and severity of the situation.
- If the motorcycle has been sitting unkept, or if you recently ridden through wet riding conditions and neglected to inspect, clean, and lubricate your chain, rust and corrosion could be why your chain is making abrasive sounds while you’re riding.
- If you’re lucky, the chain’s grease was washed out from wet weather but hasn’t yet had a chance to corrode.
- In this situation, cleaning your chain off, adjusting as needed, and applying some spec chain grease to your chain grease could be enough to get you back on the road.
If you let it sit or ride it unlubricated, the chain will start to wear and corrode, and you’ll have to replace it.
If your chain and sprockets are unaligned, it may indicate a faulty chain tension adjustment that you or a mechanic can do on the fly.
It could indicate damage to the chain or sprockets, which you can only repair via replacement.
Regardless, a properly adjusted, lubricated, and seated final chain drive should be quiet besides the quiet noise of the rollers that interact with the sprockets.
Motorcycle Clutch Grinding Noise
Grinding noises on modern motorcycle clutches can make grinding noises if the throw-out bearing, the part responsible for engaging the clutch system, is damaged or corroded. You’ll hear the grinding noise when you deactivate your clutch by pressing the lever and releasing it to engage.
When you pull in your clutch lever, the throw-out bearing moves into the bike’s flywheel, applying pressure to deactivate the engine’s momentum.
When you release the left-hand clutch lever, the throw-out bearing releases the flywheel to engage the clutch system instead, re-activating the engine power.
Therefore, if a damaged or corroded throw-out bearing is the reason your motorcycle is making a grinding noise, you’ll hear the sound as it grips the flywheel and engages the clutch.
Riding with a compromised throw-out bearing is dangerous; you should replace the damaged throw-out bearing asap.
Motorcycle Front Brake Grinding Noise
If your motorcycle makes an intermittent grinding noise from the front brakes, worn brake pads likely cause the grinding noise. This abrasive metal sound is often accompanied by handlebar vibrations, primarily during front brake application.
If the grinding has more of a squeak, there may just be some debris, dirt, or moisture stuck in the pad that will eventually work itself out.
If the squeak is consistent and starts to get worse, becoming more of a grinding sound and less subtle, the pads may be wearing closer and closer to the metal.
If the grinding noise is particularly harsh or seems to be getting worse, you may have worn your pads down to the metal and need to be changed asap before they cause damage to your rotors.
- Front brake grinding songs on a motorcycle can also be caused by a jammed brake caliper that drags your pad during brake application, causing a dragging or brushing grinding sound.
- To find out if this is the grinding sound you hear, walk the motorcycle in neutral and feel for front wheel resistance.
- If it feels like your brakes are lightly active in the front, or if the bike eventually stops on its own when you push it lightly, the front brake might be dragging.
You can confirm a sticky caliper is the culprit behind the front wheel grinding by feeling your front brake rotor with your finger after walking your bike. If a faulty caliper were dragging your pad across the rotor, the rotor would be warm from the fresh friction.
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Motorcycle Engine Grinding Noise
Grinding noises from a motorcycle engine are often signs of a bearing failure, either internally or with the wheel bearings. Either situation requires killing the bike immediately, refraining from riding it again until the faulty bearing has been replaced, or you’ve confirmed the bearings are all in working order.
- If the engine noise is accompanied by a pinging sound and sounds like it’s coming from the engine cylinder, it may be caused by an air/fuel ratio problem.
- If the air-to-fuel ratio is out of tune, the heat generated by the piston’s compression stroke can be enough to combust the mixture early while it is in the engine cylinder.
- Worn, jammed, or poorly adjusted valves can make a grinding noise that sounds like a rattle.
- Low or contaminated oil and dirty or low-grade fuel can also cause rattling and grinding noises from the engine.
Motorcycle Front Wheel Grinding Noise
The reason motorcycles make grinding noises from the front wheel is often because a rock, dirt, or road grime is jammed between the brake pad and the rotor. If the material stuck in your brakes is significant enough, you might hear this abrasive rubbing sound even when you’re not applying the brakes.
If the nose is only present when you apply your brakes, it’s likely because the front brake pads are worn out.
If the grinding noise is severe, they may be worn down to the metal and destroying your rotors every time your press the brake lever.
Finally, squeaky grinding noises coming from the front wheel of a motorcycle can be caused by the brake pad material flaking off and jamming between the rest of the pad and the metal rotor.
Sources
Top 6 Strange Motorcycle Noises | What They May Mean
