What Causes Abnormal Noises in Motorcycle Power?
3 Answers
Motorcycle power produces abnormal noises due to excessive clearance and severe wear. Below are the relevant explanations: Excessive Clearance: The piston knocking sound is usually caused by excessive clearance between the piston and the cylinder. During the engine's power stroke, the piston is subjected to high-pressure gas, resulting in noise. Severe Wear: When the big-end bearing of the connecting rod is severely worn (or loose), there is a noticeable noise during engine idling, which intensifies under increased load. Sudden acceleration (from idle to medium speed) produces a distinct continuous knocking sound (rolling bearings may also cause internal engine noise), which is the main characteristic of big-end bearing noise.
I often help friends repair motorcycles, and I think there are quite a few reasons for power-related abnormal noises. The most common is chain slackness, which causes a clicking sound while riding, especially noticeable during acceleration or deceleration. If there's a buzzing sound from the engine area, it might be due to worn bearings or insufficient lubrication, leading to increased friction between parts. Clutch issues are another cause, producing a clunking sound when shifting gears, often due to worn or deformed clutch plates. Loose exhaust pipes are also not uncommon, resulting in a rattling noise when going over bumps. My advice is to first identify the location of the noise: issues at the front are likely engine-related, while the rear could indicate chain or wheel hub problems. If the noise changes with speed, it’s probably a transmission component issue. Don’t delay—small problems can escalate into major losses, so safety comes first. Visiting a repair shop for professional diagnosis with the right tools is the safest approach. Regular chain maintenance and oil checks can prevent abnormal noises from worsening.
Last time I rode my new bike at high speed, there was a loud rumbling noise. At first, I thought it was wind noise, but upon inspection, it turned out the rear chain was too loose—the noise disappeared after tightening it. Uneven tire wear can also cause a whining sound, especially when accelerating unsteadily with old tires. As a beginner, I made the mistake of thinking small noises didn’t matter, but they can hide significant risks. Locate the issue by listening to the direction of the sound: front-end engine noises might indicate worn bearings, while rear-end chain looseness is easier to fix. I recommend walking around your bike weekly to check bolt tightness before riding. Strange noises affect both mood and handling, and poorly installed aftermarket parts—like a loose exhaust pipe—are common culprits. Addressing issues promptly saves money and hassle while preventing accidents. Sharing experiences helps new riders avoid pitfalls.
