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What is this noise from the carbs?


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I recently cleaned and tuned the carbs on my '06 RSTD.

Everything works fine except for this noise that starts only when the vehicle is stationary and idling.

I turn it off immediately. But then, if the ignition is turned on, the noise starts again. I have to give it 10-15 minutes so that the noise doesn't recur even when the engine is not on. 

Please help!

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23 minutes ago, Marcarl said:

It can be difficult to determine a noise once it's recorded and then played back, but it sounds like it might be the fuel pump.

I agree. Unfortunately I don't know how else to record this. The noise is in addition to the "whirring" sound when the ignition is turned on. Here is the video when it sounds normal. 

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It might be helpful to determine where the sound is coming from exactly, front of engine, back of engine, upper, lower, etc.

Another approach would be to remove fuses one at a time to discover the circuit that is causing it, and then hopefully trace it closer to the point.

Also removing the gas tank and/or seat might help you to locate it.

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Hard to tell on the video but it almost sounds like the starter is running on or hanging up. Instead of using the key to crank the engine try shorting across the two big studs on the solenoid to crank the starter and see if you still get that noise. If not you may have a sticking solenoid. This can happen when the contacts inside the solenoid get pitted and as a result they sort of temporarily weld themselves together after a few seconds that weld point gets red hot and the points break apart again.

If it still make a noise when shorting across the solenoid the other possibility is a faulty starter sprag clutch or starter gears the sound would be coming from the area of the stator

 

Edited by saddlebum
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3 hours ago, Marcarl said:

It might be helpful to determine where the sound is coming from exactly, front of engine, back of engine, upper, lower, etc.

Another approach would be to remove fuses one at a time to discover the circuit that is causing it, and then hopefully trace it closer to the point.

Also removing the gas tank and/or seat might help you to locate it.

Thank you. I will try that. On a side note, the turn signals are no longer working. I wonder if these two are connected in some way....

 

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39 minutes ago, saddlebum said:

Hard to tell on the video but it almost sounds like the starter is running on or hanging up. Instead of using the key to crank the engine try shorting across the two big studs on the solenoid to crank the starter and see if you still get that noise. If not you may have a sticking solenoid. This can happen when the contacts inside the solenoid get pitted and as a result they sort of temporarily weld themselves together after a few seconds that weld point gets red hot and the points break apart again.

If it still make a noise when shorting across the solenoid the other possibility is a faulty starter sprag clutch or starter gears the sound would be coming from the area of the stator

Thank you. I will have to locate these items on the mc to find out where they are. Will take some work.

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Also, the noise does not occur while riding. It starts only when the mc is idling and goes away if I turn it off and let it rest for about 15 mins. 

It started when I tried to further balance the carbs (flat head screw) and really fine tune it.  This noise starts when the idling goes down while tuning the carbs. I'm just not sure what is causing it.

IMG_20211020_191205.jpg

Edited by megablok
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On 10/21/2021 at 11:06 AM, Marcarl said:

So does this sound happen when the engine is running, or when it's off, or both.

If it happens when the engine is off it has to be electrical, so then it's time to chase down the circuits.

The noise does not start in cold start or when its running.  It only starts while idling.  I turn the mc off immediately when that happens.  If I turn on the ignition immediately after (without starting the engine), the noise starts up again.  If it let it rest for 10 mins or so, there is no noise - only the standard whirring.

Dont know what this is....

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5 minutes ago, megablok said:

The noise does not start in cold start or when its running.  It only starts while idling.  I turn the mc off immediately when that happens.  If I turn on the ignition immediately after (without starting the engine), the noise starts up again.  If it let it rest for 10 mins or so, there is no noise - only the standard whirring.

Dont know what this is....

So going by what you just said, noise is there with the engine running but when you turn off the ignition and then the ignition back on again the noise continues with the engine off. It almost has to be electrical, and I say almost because strange things happen in this world.

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12 hours ago, Marcarl said:

So going by what you just said, noise is there with the engine running but when you turn off the ignition and then the ignition back on again the noise continues with the engine off. It almost has to be electrical, and I say almost because strange things happen in this world.

I am agreeing with Marcarl on the electrical side if this is occurring even with the engine not running. Things that come to mind are Fuel pump running on due to faulty pressure sensor or wiring short, fan running on due to faulty temp sensor or wiring fault. relay cutting in and out due to wiring fault, this often sounds like a buzzer. Starter solenoid acting up again wiring fault also check your handle switch for conductive debris such as green corrosion affecting your starter button.

Edited by saddlebum
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On 10/25/2021 at 8:12 PM, Marcarl said:

So going by what you just said, noise is there with the engine running but when you turn off the ignition and then the ignition back on again the noise continues with the engine off. It almost has to be electrical, and I say almost because strange things happen in this world.

Yes. 😂 at "almost". I don't know where to start the diagnosis.

These are the questions that come to my mind:

Why that noise only when the engine is idling and not when running? Is it a TPS problem?

Why does it continue to doing that when the ignition is turned back on without the engine running - is it something mechanical in the carb that is not installed correctly?

I changed the float needle/ filter on the front-right carb. It appears to be coming from there. Is it the float?

Never seen this problem before.....

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7 hours ago, megablok said:

Yes. 😂 at "almost". I don't know where to start the diagnosis.

These are the questions that come to my mind:

Why that noise only when the engine is idling and not when running? Is it a TPS problem?

Why does it continue to doing that when the ignition is turned back on without the engine running - is it something mechanical in the carb that is not installed correctly?

I changed the float needle/ filter on the front-right carb. It appears to be coming from there. Is it the float?

Never seen this problem before.....

Take a length about 18 to 24 inches of rubber heater hose or similar. Put an ear plug in one ear and hold one end of the hose to your other ear. Move the other end around the engine listening  to see if you  can pinpoint were the sound is coming from.

Edited by saddlebum
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  • 7 months later...

So, this issue is finally resolved after 4 months of not riding because of winter.  I had forgotten to replace the vacuum hoses after tuning the carbs that caused the rattling noise during idling.  

I have fully hooked up all the hoses and rubber caps and now the mcycle is running great.  Thanks everyone for the suggestions.  

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