Whining Noise on Deceleration

[schmedly]

I have a 1982 GS850G. Lately, just after changing all my oils, I have developed a loud whine on deceleration. It only occurs when decelerating, Applying even the tiniest bit of power makes the noise disappear. I double checked all the oil levels and they are perfect. No metal on the plugs. I pulled back the rubber boot and poked the ujoint on the front of the drive shaft and it seemed firm with no movement, and no oil leaked in. It is difficult to pin down where the whine is coming from exactly. I would say it is not the motor, for sure.

It sounds sort of like the whine of tires on rough pavement but louder, and it follows the speed of the wheels, not the engine. Pulling in the clutch does not effect it when decelerating. Add a little throttle and it immediately disappears.

The bike runs and rides fine, with noticeable change in performance. Anyone had this before?

 

[rustybronco]

The noise might be coming from the rear axle. possibly ring and pinion coast side tooth wear?
does it occur at all road speeds, or does it occur around 42-47 'ish miles per hour?

so hard to tell without hearing it.

 

[wkmpt]

I have a whine when I'm decelerating, I had to have some folks ride with me to help diagnose it.

After a few miles of observation, they determined the I was the source of the sound, 'cuz I just didn't wanna slow down...



Sorry, I know that doesn't help your situation...

 

[gs road racer]

Did you change the drive line oils as well? Front and rear? Proper levels? Right oil? Should be 90W gearoil gl-5

 

[schmedly]

Did you change the drive line oils as well? Front and rear? Proper levels? Right oil? Should be 90W gearoil gl-5

Well you can't get unblended gear oil anymore in the store, so I used 80-90 gl-5 hypoid gear oil, which is as close as I could get. I used it in the secondary and the final drive. 10-40 in the engine. Double checked levels and all is well.

 

[schmedly]

The noise might be coming from the rear axle. possibly ring and pinion coast side tooth wear?
does it occur at all road speeds, or does it occur around 42-47 'ish miles per hour?

so hard to tell without hearing it.

It occurs at all speeds, but only when decelerating.

 

[gs road racer]

Possibly different oil, how many miles on the drive? as long as it's not sounding like it's going to jump out and bite you It's probably fine. If it's very loud then maybe time to check gear lash and all the nuts and bolts around the u-joint.You already said no metal in the oil right?

 

[schmedly]

Possibly different oil, how many miles on the drive? as long as it's not sounding like it's going to jump out and bite you It's probably fine. If it's very loud then maybe time to check gear lash and all the nuts and bolts around the u-joint.You already said no metal in the oil right?

Right. I am wondering if I have a bad bearing in the transmission.

 

[rustybronco]

It occurs at all speeds, but only when decelerating.

secondary or final drive coast noise. time to find out which might have excessive play in it. then you get to figure out why.

you might want to remove the boot around the drive shaft, then check for any for and aft movement at the drive flange.
#10 in this drawing.

 

[schmedly]

secondary or final drive coast noise. time to find out which might have excessive play in it. then you get to figure out why.

you might want to remove the boot around the drive shaft, then check for any for and aft movement at the drive flange.
#10 in this drawing.

I did pull back the boot and found no movement.

I guess I will have to find a mechanic to inspect the secondary and final drive to locate and fix the problem. Sounds expensive. Argh!

 

[rustybronco]

Sounds expensive. Argh!

Not really.
if you can find a cheep final drive, which can often be found for $25+ shipping, just go ahead replace it. if the noise goes away... smile!

 

[schmedly]

Not really.
if you can find a cheep final drive, which can often be found for $25+ shipping, just go ahead replace it. if the noise goes away... smile!

Do you think it is more likely the final drive than the transmission?

Thanks for the help.

 

[rustybronco]

Statistically you have a 50/50 chance. I just figure it's a cheaper alternative, unless you can find someone who is able to discern if it's an engine or final drive noise.

by what you have said, I think the odds are in your favor, it's final drive noise.

I have a used final drive, which has "some" spline wear, you could have for the cost of shipping. but I don't know how soon before I could package it up and ship it.

 

[knotzilla]

I have a whine while decelerating . Mine comes from the primary helical gear on the crankshaft which is normal, Ted

 

[schmedly]

I have a whine while decelerating . Mine comes from the primary helical gear on the crankshaft which is normal, Ted

How long have you had it? Mine just developed out of the blue. Have you always had it. How loud is it? Mine is pretty loud.

 

[knotzilla]

How long have you had it? Mine just developed out of the blue. Have you always had it. How loud is it? Mine is pretty loud.

I always had it since I bought the bike. It had 53,500km when I bought it 4 years ago and it has 94500 now. I can really only hear it when decelerating to a stop sign while downshifting. Ted

 

[schmedly]

Just for laughs I put in some heavier oil and the secondary got quieter and the final drive not so much. I used 85-140 GL-5 and it sounds better. Huh. Seems definitely related to the gear oil viscosity.