1986 VF500 - cold weather noise

So I've got an '86 VF500 that runs perfectly in temperate weather (50's-70's or so). Thing is, when it dips into the low 40's or below and I travel at a high rate of speed of 65 mph or better (i.e. pretty damn cold with windchill factored in), there's this weird noise that occurs.

The best I can describe it is as a kind of medium to high-pitched whine kind of like how a vacuum cleaner (I'm thinking particularly of a shop vac) sounds when it's on its last legs or all blocked up and just ain't working right. It sounds like it's coming from the radiator/fan area, but I can't be 100% sure. It stops when I slow down, and doesn't start until said conditions are met again.

Any ideas?

 

Only mine for past year. Zero knowledge of history.

 

^^ bingo to the above reply. It's the speedo cable. Mine does it too, if I let it sit outside for a few hours in 40 degrees or below. Once I ride a few miles it gets quieter then finally stops whining.

 

I'm definitely willing to give it a shot. However, it really only happens when the conditions I described are met, not when I first drive it after sitting in the cold. Also, it doesn't go away after driving some miles. Last night it did it towards the end of my ride as it got really cold. Also, the last speedo cable broke end of last year, so this one's brand new.

Still, I'll give it a go and report back. Thanks to all for the suggestions.

I'll obviously take more if they're out there, though...

 

Okay, then. That's good to hear.

Thanks again.

 

Here's a quick way to check if it's the speedo cable - does it follow the road speed or engine rpm? In other words, if you are moving along and pull the clutch in and let the engine go to idle, does the sound get quiter or does it stay the same? If it stays constant then it could be the speedo cable, if the sound changes with the engine speed then it's something with the engine itself.

Let us know what you find out!

 

Pretty positive that each time I've slowed down to listen better (and see if it stops or lessens), I've pulled the clutch while breaking. Since it didn't stop right away after the engine disengaged, then perhaps it's not the engine itself.

 

Now you've got the first clue. I'd say the speedo cable, or the speedo itself, would be a good place to start looking.