Strange Knocking sound Engine

Darith said:
Hello,

I have a strange slight knocking sound from my 98 st1100. link below. Any thoughts? Thanks in advance.


https://drive.google.com/file/d/1-9huOxZQh5MoGj_lDf5PcUizw4NBdf8M/view?usp=share_link

David.
Click to expand...
I tried the link, but can't view it yet.
It's not unusual for 11's to be a bit noisy on tick over, and it is sometimes a bit knocky.
Any other symptoms, I'm guessing not, but it'd be good to know.
There is some thought it might be the primary drive.
Does pulling the clutch in reduce the noise?
Upt.
 
If you have one carb badly out of synch or with a plugged pilot jet, cracked or leaking rubber manifold etc. the engine will make a pronounced knocking sound at or near idle. Anytime one cylinder is not pulling itself over or producing power at idle the ST1100 will make a knocking sound. Even a bad plug or plug wire can cause this. I could not open your link to the sound file.
 
Up loaded video. Performance does not seem to be affected nor does it speed up or increase when the engine speeds up. I was unable to upload the mp4 file: "The uploaded file does not have an allowed extension."
 
I gave access in my google drive to the video to those emails whom requested access.
 
David,
No, it's not the normal idle knocks and rattles.
Does it change with the clutch in?
What is the oil level like?
How old is the fuel? Was it parked up for the winter and was it OK before?
Could it be an exhaust blow?
The above suggestions are all good.
Upt.
 
Last edited:
Chuffy actually describes it perfectly…a rod knock is a much louder knock/hammering sound that increases in frequency and loudness with increased rpm. I’m thinking carb synch is needed as well as checking plug tightness, etc.
 
To me it sounds like a clutch noise. For example, when I start my bike cold it makes this sound 2 - 3 times (short knocks) and than it is quiet. But it is not that noisy as yours.
I can´t imagine, that such a noise can come out of engine (but someone can correct me :) ).
 
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