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Discussion Starter #1
My bike made a weird whistling noise yesterday after riding for 15 minutes or so. It started when I pulled in to stop. Engine hot, bike was just about to idle and then a pretty loud whistle that seems to becoming from low on the engine. My first thought was the coolant system. Noise stopped when I turned the bike off.

Anyone have this happen to them? Anyone have a good idea what to check out? Everything is running great with no leaking of any fluid but the bike shouldn't be whistling at me. Going to try to repeat the niose today.
 

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Almost sounds like a vacuum leak. Have you done anything to it mechanically lately?
 

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Might be the vent hole on our coolant reservoir when your radiator cap is relieving pressure.
 

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1995 VT1100C2
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Rad cap or a hose but probably your return tube from the coolant reservoir is pinched slightly or the resevoir filler cap is loose.
 

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,,,or the gas tank vent.
 

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Discussion Starter #6
I didn't get a chance to look around my bike today. I didn't really think about the coolant reserve. That's kind of tucked away might be a problem checking that out. May be the radiator cap but the noise sounds like it is coming from lower on the bike. The reserve or something to do with it makes sense.

No I have done no work on the bike in months, nothing.

It took a while to make a sound so I assume it is pressure related somewhere on the bike. I'm not leaking fluid which seems like if it was the coolant system it would be leaking somewhere? I changed the coolant maybe 3 months ago and the radiator cap was a PIA to get off making me think that might be the problem. 3 months for that to leak? That doesn't sound right to me. Seems like if something was wrong there it would make a noise immediately.

This might take a few days to check everything out. Work and my kids play baseball, the season has begun so I go watch the games not work on my bike. For those of you up North the spring school sports seasons start now with preseason games starting this week.

I had the tank off a long time ago maybe 9 months to clean out the petcock, I don't remember really paying any attention to where the vent hose was going. ???? Again seems like the problem would have started up sooner than now if the hose wasn't in the right place. My last ride before yesterday was a long one, maybe the vent hose got burnt or something?

Thanks for the replies.
 

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"Stopped when I turned the bike off "
Makes me think cooling fan.
 

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1983 Honda vt750 Shadow
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If it continues when you stop riding, but the engine is still running, it should be easy to walk around the bike while still running and listen for the noisy area.
 

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Discussion Starter #9
Problem is repeatable, strangely when I turn the motorcycle off it stops? If it was pressure related I don't think it would stop making noise when I turn the engine off. The noise is for sure low on the bike and seems to becoming from the coolant reserve area. Kind of sounds like it's coming from very near the oil filter?

My clamps are rusty on the coolant lines and the lines themselves aren't in good shape. The one on the reserve is brittle but I can't see the whole thing with out taking a chrome piece off which it looks like I can't get that off without taking the exhaust off. I can't get a socket in there or a wrench to sit right on the bolt. So I gave up for today.
 

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A few questions: does the whistling occur with a running but cool engine? Does the whistling match rpm? Does it occur at higher rpm? Could be water pump rubber impellors are wearing out but usually the pump will leak out a weep hole so check that. May as well check coolant level also.
 

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Get it warmed up to do it, and kneel down with a 2 foot piece of hose to your ear and pinpoint the source area.
 

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Discussion Starter #12
A few questions: does the whistling occur with a running but cool engine? Does the whistling match rpm? Does it occur at higher rpm? Could be water pump rubber impellors are wearing out but usually the pump will leak out a weep hole so check that. May as well check coolant level also.
No whistling on a cool engine. Has to hot to the point that the fan is starting up. Noise has nothing to do with the fan starting and stopping. This only happens at low RPM or at least I think. If I go out for a ride it takes 5 miles or so for the whistle to start but it only happens when I slow down to idle or close to idle. If I rev the bike, the sound goes away. Nothing is leaking, I checked all over the bike, there certain is nothing on the ground where I park my bike. Not a drop.
 

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I'd replace the thermostat and or rad cap, think whistling kettle, match it up with one for a Honda Civic at the autoparts store and then it is not a huge investment to see if the noise goes away,
 

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Again I mention finding the source area with a stethoscope or hose. It may even be the water pump bearing, and not have a leak from the seal. Possible anyway.
 

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So engine must be hot and running ie no noise once turned off. This indicates it is not pressurized air/fluid escaping or it would continue at least a few seconds after engine stops. It occurs when bike is stationary? If so its not wheel bearings, brakes, suspension etc. or sound of air on windshield etc. The sound goes away once rpm is up so difficult to tell whether it is rpm related but so far I think its a bearing related to mechanical. I would check the coolant and perhaps oil/filter change.

G.
 

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Discussion Starter #16
Problem solved, I sold the bike tonight. The guy was Hell bent on buying my bumble bee colored bike. As is, the only problem I have is that whistle. He rode it for a few minutes and said he would take care of the whistle. Money changed hands and off it drove to for a about an hour ride. I don't know if I would have done that with an unknown bike.
 

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1999 Shadow 750 ACE VT750CD3 Modified
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I guess being the originating poster you get to mark this one as "Solved". (-;
Congratulations.
 

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Solved.
BUT I WANTED TO KNOW WHAT THE NOISE WAS !!! :unsure:
 
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