I know you cant hear this noise..

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MikeM

MikeM

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Jun 1, 2011
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71 750 rebuilt about 500 miles or so ago.
I am hearing a whining blower type noise off idle. Not necessarily loud but somewhat disturbing. More top end than bottom.
A slight ticking also.
Someone tell me they all do it or I need to tighten my seat bolts a 1/4 turn.
Or...do I need to set the valve lifter clearance or something like that? No chunks in the oil and the bike starts on second kick and runs great.
 
Was the head ever re-torqued?

Also, just check the valve clearances. Don't ask anyone whether you should.
 
I once had an intake manifold leak on an auto do that. Sounded like a turbojet. Check your carb/ manifold fasteners.

Slick
 
Triton Thrasher said:
Was the head ever re-torqued?

Also, just check the valve clearances. Don't ask anyone whether you should.
Click to expand...

I dont know if it was retorqued. I am going to stop by the builder next week and let him take a listen.
How often to the valves need to be set?
 
no turbine whine sounds should be heard, just hi pitch tinkles of head ringing from rocker touch downs and combustion clangs into headers - so could be a chain dragging or maybe crank shimmed too tight for thermal expansion. Maybe mag rotor rubbing stator. Could just run till obvious show stopper but other wise should think of starting from crankshaft back out again. There is no rpm nor constant flow for air leaks in Commando to turbine whine as I have had exhaust, head gasket and carb manifolds come loose or blow out for distinct STACCATO blasts or spitting sounds. Would be good if audio-video for us but if description correct its sounds like bad juju from rotating parts not pulsing or oscillation features of prior suggestions. Have a nice Commando diagnosis days.
 
does the sound change as rpms are increased?
does it happen when the clutch is pulled in / released?

just guessing but...... maybe the timing chain is too tight, tach cable , or an intake leak like slick suggested.
 
Devils own job to diagnose noise , or to locate with any certainty.. I really hope its not this because its a major job, but have you thought of the sleeve gear bearing ? I had one fail in fact its the only original component to do so. This at 35,000 miles . you get a high pitched note most noticeable on tick over , blip the throttle it stops and you think you are imagining it... Do make sure the primary transmission is not too tight -and no mine never was, but worth checking.
 
Place a screwdriver tip on a place suspected to be the source of the sound, cup your ear on the screwdriver handle, move about until you zero in on it.

Slick
 
My builder tells me the noise I hear is from the rocks in my head. The engine is sound.
Now can anyone tell me what to do about these rocks?
 
MikeM said:
My builder tells me the noise I hear is from the rocks in my head. The engine is sound.
Now can anyone tell me what to do about these rocks?
Click to expand...
Pour some good scotch over them, after the ride of course.
 
MikeM said:
My builder tells me the noise I hear is from the rocks in my head. The engine is sound.
Now can anyone tell me what to do about these rocks?
Click to expand...


Take it to third party for another opinion. Hate to see you go down the road and end up with a pile of metal meal in the end.
 
pete.v said:
MikeM said:
My builder tells me the noise I hear is from the rocks in my head. The engine is sound.
Now can anyone tell me what to do about these rocks?
Click to expand...
Pour some good scotch over them, after the ride of course.
Click to expand...


I wouldn't go swimming if I was you. Your head will sink.
Dereck

Plus 6 for the screw driver test. [ you will also hear all the normal noises and wonder what the hell is going on ].
 
You have to sit in a comfy chair with a Scotch on those Rocks and view a copy of Das Boot on the telly. Keep watching the boat's engineer as he checks for noises. :)
 
Bernhard said:
Real engineers have & use a doctor’s stereoscope :!: :shock:
Click to expand...
My wife and I bought one of our kids a toy medical kit , and in it is a remarkably well built toy stethoscope that I have earmarked for my toolbox when she is tired of / or grows out of it. :D
 
cjandme said:
Bernhard said:
Real engineers have & use a doctor’s stereoscope :!: :shock:
Click to expand...
My wife and I bought one of our kids a toy medical kit , and in it is a remarkably well built toy stethoscope that I have earmarked for my toolbox when she is tired of / or grows out of it. :D
Click to expand...

Real stethoscopes will knock your ears off when diagnosing auto sounds unless you temper them with a diaphragm that is less sensitive. I put a Mylar diaphragm in mine ..... seems like it was rather thick .... 4 -6 mils or so. It still is rather loud and I use caution when applying it to a mechanical device.

Slick
 
Dances with Shrapnel said:
MikeM said:
My builder tells me the noise I hear is from the rocks in my head. The engine is sound.
Now can anyone tell me what to do about these rocks?
Click to expand...


Take it to third party for another opinion. Hate to see you go down the road and end up with a pile of metal meal in the end.
Click to expand...

I have complete trust in my builder. He says ride it, I ride it. No question.
I dont know what to listen for and he does.
I am going with the scotch on the rocks repair.
Ed at Morries Place is a Norton magician.
 
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