Metal flakes in the final drive oil

Thanks for the replys.

Ian, I'll have a good look at those vids when I get a quiet moment later. thanks.

The bike is back together since yesterday afternoon. When the box was apart and the old bearing was out, there was a lip with a black substance on it where the shim should go. I tried to move it and it didn't move so I assumed it was part of the casting. And as a result I presumed that I had no shims. It's hard to find decent pix of this part of the bike and the shims are usually refered to but not shown in Pictures. Anyway, I've reassembled everything. It was only after I sat down and once again started looking at videos and pix online about shims that I had a eureka (face palm moment) and realised I could have had a shim in there. BUT, I've no way of knowing for sure unless I take it all appart again and big bearings are bloody expensive with the exchange rate at the moment and expensive anyway.

could I just heat the bearing with one of the methods suggested and reuse it If I'm careful?

Fatnfast, My seal is a good two mm below the surface.

The bike ran great this morning. Feels much better accelerating out of corners. there is no waggle at the back at acceleration on the apex which i was finding disconcerting and unnerving.

I'm dispondant now. I've put the seal in too deep. I possibly have a shim gasket sealed to the casting and the only way to find out is to take it all appart again. Isn't it?

Would I be best buying a new seal ASAP and fitting it as it should be or will that possibly not pose any real problems down the road? Also, If I do have a shim in there stuck, is it likely to cause any problems?

In terms of the movement Doc, I was looking at nearly 5mm at the outer wheel when cold and not a lot better when hot. That's not my picture by the way, just a screen shot from a vid on youtube. I really must take photos next time for my own sanity's sake. I'm expecting a call from motorworks tomorrow, so I'll chat with them and see what they suggest. In the mean time, I plan on putting some miles up on the fish dash on Sunday and I've plans to go out again on Monday. I'm hoping any potential problems with reveal themselves over that time.


EDIT. After looking at the adv link, I'm certain there is a shim gasket sealed in there.

Also, I'm now back to 1 mm of play.

I've decided, I'm going to ride it. Maybe I just had an old bearing. The seal looked older that I am...
 
Owen Calm Yer Luggage !

Drain oil Take off outer cover heat it well so that the crown wheel yoke drops out EDIT You won't have enough hands so from a LOW height, and have a clean towel folded over several times to allow the thing to be very well cushioned before it hits the deck !!! Under NO circumstances allow that inner bearing /rollers or cage to hit something solid!!! AND make sure you don't get any Grit in it! :rob :rob:rob

While the cover is still hot (ish don;t burn yourself now!) Push the seal on through to the inside WITH YOUR THUMBS

it will go If it doesn't plonk in a bucket with boiling water and let it heat up and try again

Dry the cover off and heat it again and fit the crown wheel doofer back in again

whilst the cover is warm wipe a light smear of oil onto the out and inner of the seal and gently WITH YOUR THUMBS push it into place

The secret is to let your thumbs over lap the edge where the alloy and the seal meet so that the seal goes level with the top of the lip
 
I'll do that. It'll give me a chance to check if there is indeed a shim and if there is, take all the gasket sealant off it.

On the positive, after watching that KLT video, I understand a lot more.
 
Yup Correct about the seal

"but" Its is a C3 bearing that is used and there should be lateral movement in a C3 bearing when cold so you may have a millimetre (and a bit) at the wheel outer

Its NOT a big problem if there's a "smidgeon" of movement! If there's not that wee bit of free play, the bearing will be under pressure when hot!

DrF, I know you know loads more about these bikes than myself :bow, but I need convincing there should be any allowable detectable play in the 'big bearing'. A tiny amount of play in the paralever bearings seems to be common and does not mean failure is round the corner, but again is not desirable.
This is not from myself, but here:http://www.nmbtc.com/bearings/engineering/preload/ and was what I used as my guide.

Bearing preload is related to the issue of clearance and can be critical for the proper functioning of your bearing. A bearing needs to be fitted with a shaft and housing and will have some level of clearance, meaning there will be some give between the different parts of the ball bearing. To remove this internal clearance and create an interference fit, a preload is necessary. The preload essentially describes the process wherein a permenant thrust load is applied to the bearing, essentially using force to push the bearing so that it is secure in the groove and has no axial clearance.

The reason we preload is to eliminate that “give” in both the radial and axial directions for the bearing that exists even after the bearing is mounted on a shaft radially, where such give is highly undesirable.


Allowing the bearing to move about would increase wear rapidly I would have thought?:nenau

Sorry, I'm begining to argue like they do accross the pond :p
 
For what it's worth F-n-F, and admittedly that isn't a lot, I'm 100% with the Doc on this. I believe, rightly or not, that the bearing will last best if there is a very small amount of play when cold which disappears when up to running temperature. This will put least stress on the bearings. Sideways loading on a caged ball bearing doesn't seem like a great idea at all and to be honest I don't know why BMW didn't engineer it with a pair of opposed taper rollers the same as car hubs used to have.

I think that many of these boxes were over shimmed at the time of manufacture and that is why a lot had repeated issues, bearings being replaced with the original shimming used resulted in repeated failures.

Others went huge mileages without any issues whatsoever, I guess the shimming on those was perfect.
 
I do agree with what you say Mr P, a pair of opposed tapers seems like the obvious solution. What makes it odd is how BMW go on about setting up the preload for this bearing which would mean no play. Mine have been good for thousands of miles now with no play, I just hope this continues. Its still better than the 1200 FD though.;)
 
So, if I understand this correctly, if my final drive is ok, my 1 mm of play should disapear once the final drive has warmed up? I really hope mine does... getting very bored of this now.
 
Third times a charm :)

I hope!

I played on a few fun roads on Sunday and the seal is leaking and it's back to cowboys and Indians at the back end. I recon the previous seal on my new to me 1150 gs's second (in my keep) bevel box was gasket sealed to the outer cover to keep the oil in.

Anyway, I've been very well looked after by everyone and number three is on the way. Upgrading the pivot bearings too, so the only other thing I need is a grease gun.

How often do you grease your rear pivot bearings?

Oh err missus...
 
Why do you need a grease gun?

The pivot bearings are greased by hand. When you undo the pivot pins and remove, the inner race of the Bearing just pops out.

Regrease and refit.

:nenau
 
@steptoe

You were right. I did crash the car...

New box from motorworks is grand. Cleaned up well and has no play.

I messed up with the new bearings though. I used the new bolt to drive in the new bearing, not the old bolt. I'll need to buy more bearings. What a blunt tool I am...

Just to say, in my opinion, a wobbly back wheel destroyed my low speed handling. At high speed it made feck all difference.

Anyway, despite my foolhardiness, I pronounce this thread closed.

Thanks for all the help you lot. I really appreciate it.
 


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