Potential whine from rear wheel

[mojoguzzi]

While riding a short distance (25 miles) today, and during very windy conditions, it seems I hear a whine from the rear. I stopped at a gas station and could detect no play at all in the wheel. Seems to rotate normally. I ride with earplugs and music and don’t normally hear such. Wonder if our bikes (2020 w/ 22k miles) whine. Hmmm. Last two services done by my very reputable dealer.


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[mojoguzzi]

Also—when I stopped to check it, I noticed it was hot to the touch. Could just be the normal state of final drives. Could be the 74° sun.


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[mojoguzzi]

And it could perhaps be the Michelin Road 6GTs that were installed 2k miles ago? Maybe?


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[Grumpy Goat]

That is interesting. I would not think that it is the tire since a whine suggests a higher pitch than even a noisy tire would make, and the Michelins should be very quiet given the mission profile. To me a whine would be maybe due to the final drive gears ...? Was the final drive oil changed recently and are you sure there is oil in there? Only way to know would be to drain it and then refill I suppose.

Also, did you put the bike on the centre stand, put it in gear, and drive the rear wheel and listen for the whine? If it is loud enough to hear past earplugs you should definitely be able to hear something even at low speeds and under light loads. Just be careful doing this operation.

[mojoguzzi]

Oil was done 4400 miles ago. I did the center stand thing and didn’t hear any whine. Hmm will do an early oil change tomorrow or Monday and see.


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[Grumpy Goat]

Oil was done 4400 miles ago. I did the center stand thing and didn’t hear any whine. Hmm will do an early oil change tomorrow or Monday and see.

OK sounds like a good move. That would be what I would do short of dropping the rear drive and inspecting the rear spline. Oil is relatively cheap. Change that first and if no more whine then good. If still hearing it then drop the rear end. Also an idea ... stick a mic close to the area and record the noise. Shield it from the wind.

[BobAin'tStoppin']

I have many times put my hand on the rear drive as a check. It should never be more than warm to the touch. If it's hot, you likely have a problem in the making. Do an immediate rear drive oil change and see what comes out with the old oil.

[Duckbubbles]

I have many times put my hand on the rear drive as a check. It should never be more than warm to the touch. If it's hot, you likely have a problem in the making. Do an immediate rear drive oil change and see what comes out with the old oil.

I agree. Warm so you could hold your hand on it without discomfort. That's how all 3 of my bikes are. Hot probably means something is failing internally like bearings and might show in the drained oil, but on this design it may not as the outer bearings do not run in the gear oil AFAIK.

Frank

[darrell]

Stop by one of you local automotive parts places or even Home Depot, Menards, etc and pick up an inexpensive mechanics stethoscope. Sometimes this can help locate a noise the naked ear would not hear.

An example only of one of many brands on the market.

https://www.napaonline.com/en/p/BK_77690...lsrc=aw.ds&

[Pyrrho]

Dealers don't check or grease the rear shaft splines as part of normal maintenance, as BMW doesn't recommend it... even though owners have observed rust on on under-lubed splines after less than 16K miles.

[mojoguzzi]

Dealers don't check or grease the rear shaft splines as part of normal maintenance, as BMW doesn't recommend it... even though owners have observed rust on on under-lubed splines after less than 16K miles.

I had my dealer do exactly that 4K miles ago.

UPDATE (a bit): Changed the final drive oil--no bits, no bright metal flakes, just normal sludge at 4K on that oil. Will ride it tomorrow (things got in the way). Have an action camera mounted near the FD. We shall see.

TIA y'all

[mojoguzzi]

When I do run it in first gear on the center stand, I do get some clunking. Figure that's normal for these shaft-driven bikes (the saying about the Guzzi CARC bikes I owned was that it stood for "clanks and rattles constantly).
"

[Ray]

Agree with Darrell.
Always good to listen very closely.

Been a while since I heard something I couldn't recognize. This is my first boxer; it took me about 6 months before I got used to all the noise. The stethoscope initially came in handy to break down and figure out where all the engine noises were coming from.

Simply putting on a new windscreen at 30,000 changed the ratios of what I heard. (That was when I had my mechanic take a look at a normal - and unrusted - drive shaft.)

Probably my aging hearing and time as a cyclist/motorcyclist and musician - but I don't hear much in the way of loud, high-pitched noise from the rear.

If truly stumped, there is some efficiency and no shame in letting a professional mechanic take a ride.

[Lee]

When I do run it in first gear on the center stand, I do get some clunking. Figure that's normal for these shaft-driven bikes (the saying about the Guzzi CARC bikes I owned was that it stood for "clanks and rattles constantly).
"

Yes that's normal for a drive shaft with no load on it.
The bike is telling you to stop it

Some people complain about Michelin front tire howling.
Are you sure the noise is coming from the back?

[Grumpy Goat]

UPDATE (a bit): Changed the final drive oil--no bits, no bright metal flakes, just normal sludge at 4K on that oil. Will ride it tomorrow (things got in the way). Have an action camera mounted near the FD. We shall see.

Sounds like a good plan. Glad to hear that oil came out. I guess you didn't measure it? Chances are if there were no signs of leak then it would likely have still had the 180 ml of gear oil. The action camera mic should pickup any whine that you would have heard farther away, and through earplugs. Hope you hear nothing tomorrow.

[Grumpy Goat]

If truly stumped, there is some efficiency and no shame in letting a professional mechanic take a ride.

Absolutely agree with that, although many times those same individuals appear to be deaf as a post ...

[Grumpy Goat]

Some people complain about Michelin front tire howling.
Are sure the noise is coming from the back?

I thought those were Metzelers they were saying howled ... Roadtec 01s specifically ...

[Lee]

Some people complain about Michelin front tire howling.
Are sure the noise is coming from the back?

I thought those were Metzelers they were saying howled ... Roadtec 01s specifically ...

Metzeler and Michelin both.
My hearing is not the best and I wear ear plugs so I never hear tire noise.

[Ray]

Some people complain about Michelin front tire howling.
Are sure the noise is coming from the back?

I thought those were Metzelers they were saying howled ... Roadtec 01s specifically ...

I had a few pair of 01s - tire noise never sounds mechanical to me.

[mojoguzzi]

UPDATE (a bit): Changed the final drive oil--no bits, no bright metal flakes, just normal sludge at 4K on that oil. Will ride it tomorrow (things got in the way). Have an action camera mounted near the FD. We shall see.

I guess you didn't measure it? Chances are if there were no signs of leak then it would likely have still had the 180 ml of gear oil.

I did, actually--and spot on. Good-looking oil. Rain today will delay my finishing a video of all this till tomorrow or so