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Discussion Starter · #1 ·
I used the search, but no other issue was quite the same so here goes since it might be nothing

I noticed the 910S having a whining/whirring (like whoopwhoopwhoop) noise on deceleration.
At first i though "shit there goes the rear bearing", but then i started to notice the following things

- it's only there in 4th gear, decelerating from 80km/h to 70km/h
- it's there in 5th gear, but a LOT less loud, decelerating from a higher speed
- in both gears it happens at say a deceleration from 5000 to 4000 rpm
- it goes away if I pull the clutch
- it's not there in 2nd, 3rd or 6th


now i might just as well be going crazy or worrying about nothing, but does anyone have a suggestion on this?
 

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Hrmmmm, that is a head scratcher. First thought by reading the heading was drive chain to tight. However, that should be heard in every gear. Next i thought well maybe a bearing on the clutch side, or the tranny out put shaft due to no noise if clutch pulled in. Then i got to wondering if for some odd reason it could be some slack/play in the timing chain assembly which only reveals itself at a certain rpm & load. Maybe the timing chain tensioner spring is wearing out, or could even be a guide plate is loosening or getting worn thin???

These are all just pie in the sky guesses and probably have nothing to do with your issue so don't get to worked up over what i said. Just throwing some ideas out there but none are based on personal experience. Hopefully someone with the same issue will see the thread and be better prepared to provide some explanations.


BTW, have you actually checked the rear hub to rule it out?
 

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Discussion Starter · #3 ·
As i don't own a torque wrench or have any experience on disassembly of something like the rear hub, I have not taken it apart yet. However, if it would be hub related, it's not too logical that it only seriously manifests itself in 4th gear and is at a different speed in 5th?
 

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That's the problem right there.......you are looking for a "logical" explanation for something on an Italian bike. Think of it as an Italian woman.....logic has nothing to do with it.

Surely there are some threads on checking a rear hub without a full disassemble somewhere on the net.
 

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Discussion Starter · #5 ·
well, the only thread or subject i found that related to my issues was the rear hub bearings, but both of them had a consistent noise related to speed.
 

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Discussion Starter · #7 · (Edited)
Would it be helpful to do a proper oil change?
Previous owner did one last year, but since the box and clutch are lubed by the engine oil, I though it could maybe be a good idea?

Oh yeah, i did forget to say this before, but I was doing a buttload of slow-ass group riding that day, with average engine temps of 95° and more.
 

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It can be so resonance in the whole bike with different components in those specific circumstances.
And an engine oil change never harms so that would be a good option.
 

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Discussion Starter · #9 ·
someone else pointed out to me that this could be quite normal due to the bike having straight cut gears, especially since the noise is gear-specific and only under engine braking

is there logic in this ?
 

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No, no logic to that. Its not normal for a gearbox to make that kind of noise. If it is in fact coming from the gearbox(highly doubtful) then you have some gears that are trashed and on the way out. One should be able to see remnants of the gears in the bottom of the oil pan. Or if you have a magnet on the back side of your oil drain plug lots of shavings/pieces should be attached to that.
 

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Discussion Starter · #11 ·
Well, honest to god, I can't really tell where it is coming from since it only happens on decel, in 4th gear, between 80km/h and 70km/h. That's really difficult to recreate in the garage.

I'm gonna do an oil change soon, and i've contacted noel to see if he can maybe include bearings for the rear hub. I'll have to find someone to put them in for me as I don't have the proper equipment for that, but I recon that shouldn't be too much of a problem.

I was thinking about the cam chain too, but it would seem strange for that to be gear-related no?
 

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My F4 used to make a little whining noise on decel. I worked out fairly sharpish that the front mudguard was ever so slightly grazing the tyre when braking/ decel.

A little tug and all was well :)

Hope yours is as simple ..but would advise to look for simple first.

Joe
 

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Discussion Starter · #13 ·
thanks for the suggestion :)

for peace of mind, and the rather reasonable cost of it, I'm gonna change the hub bearings anyway. even if they're still in good shape, I have no clue how well the previous guy looked after them. he changed the front bearings because they were getting noisy so better safe than dead :)
 

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eh, so what was it?
 

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They got a deal on the bearings. Sssssssttttt ;)
 

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Hi, did you solved the problem? I just bought a 2010 f4 (new model) and I am experiencing the same problem. While the engine is revving down i here a buzzing noise around 5-6000rpm. Its noticeable in every gear.
I am picking the bike up tomorrow, I noticed it during the test ride.
Should i still buy it?


Sent from Motorcycle.com App
 

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These kind of things is very hard to judge without riding it. What is for one a strange sound is for the other normal. Let your feeling go over it and try to figure out if its accetable or not...
 
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