Loud high-pitch whine at idle?

Joined
Apr 30, 2017
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Bedford, MA
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2010 Silver NT700VA
Hey gang, question about scary noises.

I'm new to the NT, had it for about two months. I noticed a few weeks ago this *really loud* mid-high pitch whining noise when I was idling at a stop light. It may well have been there the whole time and I was too busy "learning" the bike to notice, but since I heard it, I can't stop hearing it. At anything over 10-15 mph, the engine sound and exhaust drown out the whine, but at idle, it's very noticeable to me.

Is this the fuel pump? Some kind of impeller? The valves or related piece of machinery associated with making engines go? Just looking to see if this is a "feature" of the NT or if it's something I want to try to explain to my mechanic...

I searched the forums and I see some people saying it's part of the drive train, but they hear it when at speed, so not sure if this is the same thing. Any ideas, comments, thoughts? Thanks!!
 

Phil Tarman

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Carge, it doesn't sound like anything I've ever heard. Of course, my hearing's shot and I almost always wear ear plugs.
 
Joined
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Genoa, IL, USA
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I'm thinking vacuum leak. A few things you can check: throttle body clamps, vacuum hoses for a tiny hole, o-rings at the throttle body holders (carb holders in old-school terms) may be flattened out.

Hope this helps.

Brad
 

mikesim

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I've not heard that noise, but I'm like Phil, I couldn't hear an elephant fart in church!

Mike
 
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Vacuum leaks make their presence known at idle, that's when engine vacuum is highest. Air whistles through tiny gaps in o-rings, gaskets, and gaps, making the high-pitched whine noise. Vacuum drops when the throttle blades open, making the whistle goes away.

Brad
 
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Apr 30, 2017
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Bedford, MA
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Hey thanks guys. Vacuum leak... sounds like something that to properly diagnose / isolate would mean taking off the fairings and lifting off the tank? That sounds ugly... well outside of my capabilities. Is this the sort of thing I need to get taken care of right the heck now (like, engine is at risk of crapping out on the highway) or something that can wait a few days? I'm not having any other symptoms that I've noticed (like rough idle, hesitation, misfires, anything like that).
 
Joined
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Melbourne, Victoria, Australia
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If it is running normally you do not need to panic.
Get it checked at your convenience.
Your description does not match anything that I have heard either other than fuel pump whine and some fuel pumps are noisier than others.
It may be that.

Macka
 
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Apr 5, 2011
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Great Plains
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It has been awhile since I owned an NT, but i remember the only time the fan came on was on warm days sitting at stop lights or in slow traffic. As soon as speeds were fast enough to move air through the radiator the fan would shut off. I also remember the fan being noisier than I liked and having a kinda high pitch.

Is it possible it is just the fan coming on when stopped or at slow speeds? Does it only do it after the bike has been running for awhile, or can you hear it at idle right after you start it up when the engine is still cold?
 

mikesim

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It has been awhile since I owned an NT, but i remember the only time the fan came on was on warm days sitting at stop lights or in slow traffic. As soon as speeds were fast enough to move air through the radiator the fan would shut off. I also remember the fan being noisier than I liked and having a kinda high pitch.

Is it possible it is just the fan coming on when stopped or at slow speeds? Does it only do it after the bike has been running for awhile, or can you hear it at idle right after you start it up when the engine is still cold?
Good man!! I fergot about the fan, betcha that's it!

Mike
 
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If you were at a stop light, the probability is very high it's just the radiator fan.
It takes almost no time st all for the temps to trip the fan when you're not moving
 
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Apr 30, 2017
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Bedford, MA
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2010 Silver NT700VA
Update:

First off, thanks everyone! I really appreciate all the help.

So, to address the radiator fan thing - I know it's not that, because I that's a *different* sound that I hear, and it acts exactly as you all described. I can hear it kick in - especially when I'm sitting at stop lights, etc - and it's a very different sound than the mysterious high pitch whine.

I'm beginning to think the whine is actually the fuel pump just being a fuel pump, as Macka suggested. Things I've noticed - when I get down to about a 1/3 or 1/4 of a tank, the high-pitched whine dramatically decreases in volume. Not sure why that would be. Perhaps some kind of blocked vent or air intake or something, making the pump have to work harder when the tank is full? Sometimes (with a fuller tank) the whine starts as soon as I start the bike up. As I work through the tank, it seems the whine doesn't start right away, it takes maybe 30 seconds or a minute before I notice it.

In any event, I'm less panicked now, so thank you all! I'll just start putting some dough aside in case I need a new fuel pump at some point... and when I take it in for a check-up before my big summer ride, I'll ask them to check the fuel filter and vents, maybe, to make sure that's not the problem.

Thanks again, y'all!!
 

Woodaddict

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my fuel pump started making noise when I turn key on @108K. but only makes noise when key is on, goes away when started. when at dealership when adjusting valves, they said sounded like a bearing in pump. they said should be ok, now have 166K with same noise
 
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