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Motorcycle Engine Noise When Accelerating: Causes and Troubleshooting

The roar of a motorcycle engine can put a smile on any rider’s face. But have you ever noticed an unusual noise joining the harmony? A clunking here, a tapping there – sounds that don’t quite belong. If you’ve experience mysterious rattles or knocks when opening the throttle, you’re not alone.

But what does the motorcycle engine noise when accelerating mean? When should you worry? And how can you keep your bike singing instead of shuddering? Read on to get acquainted with the most common sources of unwanted acceleration audio, their potential consequences, and most effective remedies.


  • Common acceleration noises like ticking, knocking, chain noise and their causes
  • Prevent noise with proper fuel grade, warm-ups, avoiding stress on engine
  • Potential damage from unaddressed noise like wear, pollution, costly repairs
  • Inspect high-mileage components regularly to catch issues early
  • Address overheating or detonation right away to prevent engine damage
  • Monitoring unusual noises can help diagnose small problems before they worsen

What Are the Common Engine Noises?

Let’s find out what the common engine noises are:

Ticking Sound

If your bike starts making a rhythmic tick-tick-tick when you twist the throttle, those valves may be acting up. A lot can cause that sound – loose valves, worn valve guide seals, even a slacking off valve train.

As the engine revs, the valves tap against the cylinder head like someone knocking on a door. Now usually it’s no biggie, but you don’t want them tickers getting out of tune.

The fix? Time for a check-up. A good mechanic will check your valve train. May just need an adjustment to the clearances if they’ve stretched a bit. Don’t ignore it though because it can lead to bent valves bumping around in there if left too long.

Knocking Sound

This one needs attention, pronto. A heavy diesel-like knock coming from deep in the engine means something ain’t right with those crankshaft bearings or rods. Could be worn bearings letting the crank wobble off rhythm. Or cracked rod bearings turning your rods into bucking broncos.

Whatever the cause, don’t try to muscle through it. Bad vibrations can quickly turn your block into an expensive paperweight.

Have a technician trace the noise right away. If the damage isn’t too severe, a rebuild might fix things up. But sometimes those knocks mean a new long block is in order.

Clattering/slapping Sound

Ever get a crazy slap-slap-slap from the top of your engine at idle or low RPM? You’re probably hearing Ol’ Faithful’s cam chain saying hello. Nothing kills the vibe of a ride like a cam chain that’s seen better days.

As they age, those roller links get loose and that puppy starts slapping around in there. If left, it’ll drive you bonkers! But more importantly, a too-stretched chain can jump teeth, messing up your valve timings but good.

Luckily, easy fix once you catch it in time. Just replace that worn chain with a fresh OEM or aftermarket link. Quick swap and your cams will dance smooth once more.

Other Possible Sounds

Sometimes you’ll catch odd sounds your bike wasn’t born with. Could be a light pinging under heavy acceleration – detonation warning you the fuel’s too low octane. Spark plugs crackling or misfiring? Could be worn out too.

And watch for a strange “bonk-bonk-bonk” that gets louder when you rev it. Feel like someone’s whacking the bottom of your motor with a hammer? Could be early detonation destroying parts from the inside out.

Moral is: don’t ignore bizarre noises. Strange sounds mean strange things, so get your local shop involved before things get too strange!

Causes of Motorcycle Engine Noises

You can’t solve the problems if you don’t know what’s causing them. So, let’s find out the possible causes of motorcycle engine noises:

Improper Combustion

A lot of unnecessary racket starts with how well (or not) things are burning up top. Over time, gunk and crud can build up in the combustion chambers. Then when you whack the throttle, it can ignite too fast or unevenly – ka-boom! – and cause all sorts of denting pings.

Too rich or lean on the fuel-air mix has a similar effect. Either way, you’re not getting an even burn. Ignition going off half-cocked for some reason doesn’t help either.

Best way to avoid all that? Keep things clean as you go with the occasional fuel system service. Proper jets and ignition timing aren’t too hard to check yourself.


We’ve all been there – hitting the gas a little harder than we should in top gear. But remember, these powerplants love to breathe cool, not crawl up the temp gauge like a prime rib on the grill.

If the bike starts running hot, ease up or find some shade. Overheating causes all kinds of delays and spots in the burn cycle. Pistons get too cozy in their sleeves too. Before you know it – boom, boom, boom – it’s knock city!

Stay on top of fluid levels and cooling system cleanliness to avoid regrets down the road. Your poor motor doesn’t need the extra heartbreak.

Low Octane Fuel

We’ve all been tempted by the lower price sign at the pump. But using gas below your bike’s minimum octane rating is begging for engine knock. Octane measures a fuel’s ability to resist pre-ignition under heat and pressure. Too low and you get spontaneous explosions inside the cylinders.

It’ll make your bike sound like it’s drinking cement shakes. Avoid, unless you’re jonesing for a rebuild. The few extra bucks for higher-test fuel protects your investment.

Mechanical Issues

When mechanicals get tired, they certainly let you know. Loose or worn bearings knock around like a pinball machine. Weak flywheels can’t keep the vibration down. Tired water pumps circulate lukewarm juice. Stretched timing belts ruin the rhythm.

If maintenance has been lacking, pay attention to any new weird sounds. Might save you hassle to have those high-mileage parts inspected. Replace them before they ride off into the sunset – in your engine block.

The Possible Damage from Unaddressed Noises

  • Pollution from unburnt gases
  • Accelerated engine wear
  • Potential for costly repairs or replacement

When those kabooms and pings go unchecked, it ain’t just your engine taking a beating. All those unburnt hydrocarbons float on out the pipes as extra pollution. Not cool for air quality or your conscience. Over time, premature detonation also dramatically speeds internal wear. Before long, blown rings and scuffed cylinders may require major bank-breaking services.

Whether it’s a subtle tick or full-on knock-a-thon, strange noises are a symptom something ain’t right. Ignore them and the problem grows exponentially with every mile. Eventually, the engine damage spreads beyond economical repair scope.

Just imagine: that valve tappet you thought was no big whoop eats a hole in a piston. Now a fresh long block’s your only hope. Could have been a cheap adjustment if you hadn’t procrastinated tune-ups!

Moral of the story? Strange sounds demand prompt inspection. Don’t let minimal troubles mushroom into maxed-out credit cards. Nip it early!

How to Prevent Motorcycle Engine Noise When Accelerating

Now you want to tame the roar when twisting the throttle, right? But how? Well, read on to discover several simple techniques you can easily apply.

Use Recommended Fuel Grade

We all get tempted by the cheap gas sometimes. But putting low-grade fuel in your buddy’s tank is a sure way to introduce her to some new knock-knock jokes! Instead, only put in what the manufacturer recommends—at minimum. Higher octane means less tendency for premature pops and bangs under pressure.

If the bike still starts acting up, it may be time for an oil change too. Dino juice accumulates contaminants that can cause similar migraines. Staying on top of fluid quality helps ensure smooth sailing.

Warm up Engine Properly

Waking up cold cylinders is asking for trouble. Give your pal a few minutes to get her blood pumping before hitting the streets. An extended warm-up allows all her moving parts to loosen up nice and gradual like.

Revving madly right out of the driveway is a good path to that money-sucking mechanic. Be gentle as temperatures rise to avoid stress cracks and excess wear on startup.

Avoid Unnecessary Engine Stress

We all get thrills from opening her up now and then. But constantly riding on the ragged edge is a surefire way to annoyance-Ville. Going balls to the wall is a quick path to stress fractures and burnt valves. Leave the top speed runs for the track.

Cruising along at a good clip is one thing. But easing up on those full-throttle bursts lets your pal live to ride another day without incident.

Address Overheating Quickly

Even the best of us get a little carried away in hot weather. But don’t let her overcook – pull over and let that system breathe! An overheated bike sounds nasty and works nasty too.

Ain’t no engine noise worse than the death rattle of a fried top end. Spare yourself (and wallet!) the grief down the road.

Inspect High-Wear Components Regularly

Parts that move mean parts that deteriorate. Over many miles, those fragile bearings, chains, and sprockets can quietly diminish while you ride. Avoid disaster down the line by giving the bike’s vulnerable bits a peek every few tanks.

Catching worn sliders, slack rubbers, or stretched rollers saves a world of hurt later on. Replace or repair what’s looking risky, not what’s already broken. An ounce of inspection is worth more than a pound of cure, as my old man always said.

FAQs About Motorcycle Engine Noise When Accelerating

What’s the issue when a bike makes a light knocking sound at idle that goes away when accelerating?

A single tapping knock at idle often indicates a loose or worn valve tappet. Have the valve clearances inspected – an adjustment may fix it. Monitor to ensure it doesn’t worsen.

I notice a rattle that seems to come from the top end around 4000 RPM. Anything to worry about?

A rattle isolated to higher RPMs could be related to the cam chain or tensioner. Inspect for excess slack or worn parts. No immediate danger but don’t ignore – it may need attention soon.

My bike has 50,000 miles and is starting to make some weird clunking noises. Time for an engine rebuild?

Not necessarily. Have a mechanic thoroughly inspect for the source – it could be something simpler like worn suspension bushes. Only rebuild if actual engine damage is found. Replacing high mileage parts is often a more cost effective first step.

I put 89 octane in my bike that requires 91. Will one time cause damage?

Likely no permanent harm from one tank of lower octane. But use the recommended grade or higher from now on to prevent long-term problems from detonation like preignition or ringing noises.

My engine makes popping sounds under heavy acceleration. How much of an issue is this?

Pops could indicate an ignition issue allowing unburnt fuel into the exhaust. Have the plugs, wires and ignition timing checked – it’s better not to ignore potential problems. Catching small issues early prevents costly repairs down the road.

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