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Motorcycle Repair/Knock in top end of motor


What would cause a buzzing sounding knock in the top end of my 2003 suzuki rm85? The motor has plenty of compression.

Hi Joe,

It could be a loose exhaust or even a broken piston ring.
Best thing is to hold a long screwdriver to the engine and
try to locate the noise  by ear.

Noises. all have difference frequencies.
Low knocks or growling rumbles are usually
in the bottom end of the engine.

Higher pitch slapping. or ringing are near the top
in the cylinder area.

Reed valves and exhaust valves  might make a buzzing noise.

Squeaking noises might be a bad head gasket or seal.

If you can locate the sound that might help in deciphering what it is.

A broken ring or piston is best fixed right away.


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Wayne S.


Licensed Motorcycle Mechanic, Knowledge of motorcycles from 1960 up, Japanese, British and most other brand motorcycle repairs.


Worked for Yamaha, Honda, Suzuki, Kawasaki British: Triumph, Norton, BSA Other: Most Scooters and Mo-Peds

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