Whine,squeal, singing noise?

[spiney]

1981 has a high frequency noise around 2-3 thousand revs not there on start up but quickly appears as soon as engine warms up. Sounds like its coming from the very front of the engine. I have replaced both rotor (not stator) and bean can but no change. There when stationary or underway pull in clutch lever no change. Have a mechanic mate with a lot of airhead experience but as he has a very steep industrial high frequency hearing loss he can't hear it very well?? Any ideas?

[wilcom]

Have a mechanic mate with a lot of airhead experience but as he has a very steep industrial high frequency hearing loss he can't hear it very well??

Since it is soo hard to type a noise.........any chance of taking a video(with sound ) and posting to Youtube so we could all have listen ?

[spiney]

Yep I'll get a video with sound as soon as I can.

[Kelvin]

I once had a noise that would answer that description after replacing the camchain. Squeaking at only a particular rev range, and only under power. Because I heard it only under power I only noticed it when riding the bike, not in the garage. The fact that you only observe it warm also suggests camchain: a worn camchain is often quiet on startup, only audible when warm.

Solution was to take the timing cover off and adjust the chain guide carefully.

How long since you've replaced the camchain? I would expect to do it at 80k km.

[spiney]

Kelvin unfortunately I have very little knowledge of the bikes history although pretty sure its only done 50,000K. Have not inspected the cam chain but it may be an idea. Far too wet today to have a ride and record the noise.

[spiney]

Took me a while but I put a video on u tube https://youtu.be/uJwQGamFL0Q

This is after a 15 min ride around the block.

[donbmw]

Saw your post on Facebook. I didn’t hear anything that sounds abnormal.

[wilcom]

I hear the sound between 2-3000 but, like Don said,  it just sounds like normal Beemer stuff to me.

[Bob_Roller]

Do you have a mechanics stethoscope ??

You could try having someone else operate the throttle while you put the tip of the scope on various parts of the engine .

I listened to the video and did not hear anything out of the ordinary either .

You could check the exhaust system for looseness and fasteners in the area .

[Kelvin]

I also heard nothing out of the ordinary, so my hypothesis about the camchain is looking a bit weak.

In addition to checking the exhaust system you might check the air intake: you don't have a whistling cable in front of or leaf stuck inside the air intake horns?

[tunnelrider]

Had a look at the video - the whine sounds a bit different to me how it exists under no load - I do get a slight whine when attempting hard acceleration low down the revs under way, I always thought it must be the much read about induction 'roar' (I'd hardly call a roar).

In addition to checking the exhaust system you might check the air intake: you don't have a whistling cable in front of or leaf stuck inside the air intake horns?

Good point Kelvin I think I've always had a cable in front of the intake horns

[spiney]

Thanks for all the tips I will check everything suggested. I do have access to a mechanics stethoscope so will borrow it and see if I can zoom in a bit.

[Luca]

Thanks for all the tips I will check everything suggested. I do have access to a mechanics stethoscope so will borrow it and see if I can zoom in a bit.

often you can get away with just holding your ear to the handle of a long screwdriver and placing the business end at your inspection points.  I can hear a little bit of a whine, but nothing unusual.  It actually sounds pretty good to me!