Strange whine when cold at speeds over 35km/h?

Hello guys, I have an odd issue here that maybe you could help me out with. My bike (84' 750) makes a ridiculous whine while riding at speeds over 35 km/h (21mph) when it's cold out. Eventually when the engine warms up enough, the noise mostly goes away. It has nothing to do with engine speed, and only when the temperature is below 10C (50F). It sounds like it comes from the front of the bike, but I have no idea what could be making it!

When at a stand still there is no whine. I accelerate and hit 35-ih and it starts up, but when I slow down, it doesn't go away until about 15 km/h.

I'll try and get a video of it making the noise.

I'm stumped though haha!

 

I've had the same problem, my mechanic thought it might be the speedo
but we are stumped as to where the noise is from. Hopefully some one will
ring in with an answer, I'll be watching goodluck.

Garry

 

My bike is in getting the valves adjusted, but when I get it
back I will disconnect the speedo cable just to see if it changes.
I'll let you know.

 

Yes, speedo cables do need occasional lube. If you can get the front end up, spin the wheel and listen for your noise.

 

Should I just use regular oil like the shop manual said or is there a trick that you've come across that works better?

Thanks again!

Also Lobotomy, where are you getting your valves looked at? No one in town will touch my bike with a 39 and a half foot pole :S

Cheers!

 

You need to find an old, established shop that's been around for at least 25 years and find a bald old man who loves 'cycles and get him to do the work. I'd never let anyone under 40 touch my bikes.

Checking valve clarances is not necessarily a professional job if you have basic skills.

 

A recommended oil over here for cables and the like is Silkopen by Silkolene. It's an aerosol, very thin lubricant (like WD40) but it also has graphite suspended in it. You might find an equivalent over there. Some of the aerosols have solvents that can swell the polymer lining of the cable making the cable very hard to move.

 

Do what the Squirrelman says I looked around for a while here in TO
and found a couple of guys ( both older than me and I'm 57) that love
working on older bikes. Check clubs or forums in your area and see
what people say about their mechanics. Also make sure you have the
factory service manual ( which I believe you download somewhere on
this site in files I think) as you will find it easier to work from. Just
remember that the older some of us old farts get the slower we work,
so the old guys might not be the fastest, but they always do good
work and usually try to save money also. If you check my gallery out
you will see a picture of my front cam which was just redone, and
compare to yours. These guys do cams but I don't know about valves
Home. Good Luck

 

So trefmawr did you find the solution to this? I'm currently experiencing the same issue and I'll be pulling the speedo cable and lubing her up to see if that is the culprit. I was also wondering if perhaps it could be one of the fans since it is happening at speed. I'll try and remember to chime back in with the answer if I find it.

 

Occasionally I have had the same issue but with some careful troubleshooting I found out that it was just my wife. She quiets down as she gets colder (when I speed up) LOL :chaingun:

Sorry I just couldn't resist! I looks like the technical responses are already posted anyway so a grin is a good as a fix I say.

 

That is strange. I normally get that whining immediately before and after a ride, not during. If you do not have a passenger the speedo cable sounds like a good possibility.

 

Just lubed up my speedo cable (dab of oil) and no more noise. Did you find any old guys yet?

 

Hmmmph...I just lubed mine (dab of oil) and it's still making noise. ?!?

 

Perhaps check your chain. When was it last serviced or chained?

 

Well...I took the instrument cluster apart and got some lube into the speedo input shaft bushing/bearing. So far so good. Bike no longer needs any cheese for all that wine!