Gearbox Bearing Numbers

Pukmeister

Pukmeister

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Hi, does anybody have a list of alternative bearing numbers for the later GS/GSA hexhead gearboxes ? Mines a K255 0380 GSA with the enduro first gear, built in 2008/9. I'm sure I saw a list of Koyo bearings somewhere, but searching online has been fruitless so far.

BMW use an unknown numbering system from their suppliers NSK for these bearings. I can always buy quality double sealed bearings in the necessary standard sizes from my local supplier but not sure which type of fit to order eg standard, C3 etc ??

As usual, somebody in the Fatherland is taking the piss with pricing. After having my pants pulled down for over £400 for an input shaft, I am running low on vaseline.
 
Pukmeister said:
Hi, does anybody have a list of alternative bearing numbers for the later GS/GSA hexhead gearboxes ? Mines a K255 0380 GSA with the enduro first gear, built in 2008/9. I'm sure I saw a list of Koyo bearings somewhere, but searching online has been fruitless so far.

BMW use an unknown numbering system from their suppliers NSK for these bearings. I can always buy quality double sealed bearings in the necessary standard sizes from my local supplier but not sure which type of fit to order eg standard, C3 etc ??

As usual, somebody in the Fatherland is taking the piss with pricing. After having my pants pulled down for over £400 for an input shaft, I am running low on vaseline.
Click to expand...

Here are the parts number and the size for each of them, the size probably being the interesting part.
https://www.realoem.com/bmw/enUS/showparts?id=0380-EUR-02-2008-K255-BMW-R_1200_GS_Adve_08_0380,0390_&diagId=23_1108

They also mention x613 = Yes or No.
I'm not sure what this means, my wild guess would be sealed or not sealed.

As for C3 option, this is usually used for bearings working under extra warm conditions. I have never heard of the C3 option being used in any BMW motorcycle .
 
Thanks Knutk, I didn’t expect to need a radial clearance C3 bearing instead of a standard fit, but didn’t want to assume wrongly. I have found the Koyo bearing numbers except for the output shaft spline end bearing which seems to be NSK only.
 
Pukmeister said:
Thanks Knutk, I didn’t expect to need a radial clearance C3 bearing instead of a standard fit, but didn’t want to assume wrongly. I have found the Koyo bearing numbers except for the output shaft spline end bearing which seems to be NSK only.
Click to expand...

The 20 x 52 x 15 bearing has the SKF number 6304.
Perhaps this shop may be of help?
https://www.bearing-king.co.uk/bearing/6304-2z-skf-shielded-deep-groove-ball-bearing-20x52x15mm/4348

They list the -2Z bearing in this link, but if they are not able to get the unshielded bearing, prying out the shields are no beag deal..
 
All my gearbox shaft bearings are shielded, the only unshielded bearing is in the selector drum ?

I have researched the following numbers:

INPUT SHAFT ENGINE END 23 12 7 709 852 52x20x15mm KOYO 6304 2RS x1
INPUT SHAFT FREE END 23 12 2 330 176 20x47x14mm KOYO 6204 2RS x1
LAYSHAFT BOTH ENDS & OUTPUT SHAFT ENGINE END 23 12 7 709 798 56x22x16mm KOYO 63/22 2RS x3
OUTPUT SHAFT REAR END 23 12 7 709 809 62x25x17mm KOYO 6305 2RS x1

I also have an alternative of NSK 63/22DDU for the KOYO 63/22 2RS

I now have it on good advice to go for a C3 fit. Makes sense as these gearboxes run pretty bloody hot.

"Simply bearings" and "Quality Bearings Online" have stock, as does my local supplier BRT bearings.
 
Rereading my post #5, I realize the bearing that I mentioned was the bearing for the input shaft. Sorry, my bad. It will probably happen again :friday

@Pukmeister: Interesting info about the C3. I will make a mental notice :beerjug: :okay
 
knutk said:
@Pukmeister: Interesting info about the C3. I will make a mental notice :beerjug: :okay
Click to expand...

My old Yamaha YZF-R1 4XV also had C3 gearbox bearings so I guess its not uncommon. Bearings and Input Shaft should hopefully arrive soon and I can rebuild it and see if it has quietened down instead of the Ducati-like rattle in neutral I was getting.
 
knutk said:
As for C3 option, this is usually used for bearings working under extra warm conditions. I have never heard of the C3 option being used in any BMW motorcycle .
Click to expand...

Knut You better go do some more research!!!!

Large FD bearing is C3 on all the R11XX R850 etc etc

Standard in Gearbox on Airheads and I VERY much suspect the same for any later Standalone gearbox

If you run C0 or C 1 where does the oil go to cushion the contact?
 
DrFarkoff said:
Knut You better go do some more research!!!!

Large FD bearing is C3 on all the R11XX R850 etc etc

Standard in Gearbox on Airheads and I VERY much suspect the same for any later Standalone gearbox

If you run C0 or C 1 where does the oil go to cushion the contact?
Click to expand...

:D:D:okay

I have always been under the impression that if no Clearance is stated, this meant C2.

Now that you print the above, I have googled the subject, and I find claims of 'Standard as anything from C2 to C3 and tolerancecs inbetween. SKF says 'Normal is > C2 and < C3.
Since BMW does not mention C-class in their specification, I have taken it for granted that they use the 'Normal or Standard' class.
However, if 'Normal is not available, I do agree that going C3 is to be preferred over C2. Of all the bearings I have changed (I can easy cont them using hands and feet) I have never seen one marked either C2 or C3, but I can not exclude the fact that not every manufacturer do like SKF and mark their bearing when not 'Normal.

Even so, I do agree that I may always do more research, but please don't tell my wife...:beerjug:
 
The issue with the original bearings used by BMW at the factory is they use a non-standard identifier so you cannot easily cross-reference them with the standard bearings that are commercially available from bearing suppliers.

The ready-built input shaft I have on order from Germany should have brand new bearings fitted so at least that is a few quid saved, the other bearings cost me £60.53 including vat and delivery. All existing shaft bearings seem perfect at 50k miles but whilst its apart it would be foolish not to replace them.
 
Thanks for the link, but I don't buy into the description given of seals 'filtering oil'. They do prevent the ingress of contaminants.

A bearing manufactured with seals is just a bearing with rubber seals pressed in.

The channels put into the casting during manufacture are most likely because the bearings are fitted blind into the casings and are an interference fit, so the channels will let air behind the bearings vent out as the shafts are installed into a heated/expanded casting and let the casing 'breathe' rather than getting air trapped behind the bearing which could expand when hot and cause issues like blowing the rubber seals out, or prevent the shafts from fully seating during installation due to a pocket of air stuck behind them.

According to the NSK website, a TM bearing is just a low friction seal:

https://www.nskeurope.com/en/nsk-in...nsmission-bearings-low-friction-tm-seal.html#

I can't see how the 2RS double-sealed Koyo bearings I have purchased would be measurably any higher friction than the NSK double sealed ones that are fitted in the factory.
 
Maaaan... I'm learning something new evey day :D :beerjug:

Out of curosity, and with no better things to do, I looked into the webpage of MotorWorks.
As you know, they sell bearings for use in in the gearbox (and yours truly has been one of their customers)

They also show pictures of the Non-BMW (but correct size) bearings. And what do you know? Blowing up the pictures, most of the bearings are -C3, even for older bikes like for my 90S.
Good thing then that I ordered the bearings from them rather than just any random source. (Saved by the bell :p) :jager
 
Pukmeister said:
Thanks for the link, but I don't buy into the description given of seals 'filtering oil'. They do prevent the ingress of contaminants.

A bearing manufactured with seals is just a bearing with rubber seals pressed in.

The channels put into the casting during manufacture are most likely because the bearings are fitted blind into the casings and are an interference fit, so the channels will let air behind the bearings vent out as the shafts are installed into a heated/expanded casting and let the casing 'breathe' rather than getting air trapped behind the bearing which could expand when hot and cause issues like blowing the rubber seals out, or prevent the shafts from fully seating during installation due to a pocket of air stuck behind them.

According to the NSK website, a TM bearing is just a low friction seal:

https://www.nskeurope.com/en/nsk-in...nsmission-bearings-low-friction-tm-seal.html#

I can't see how the 2RS double-sealed Koyo bearings I have purchased would be measurably any higher friction than the NSK double sealed ones that are fitted in the factory.
Click to expand...
Not being a proper motorcycle mechanic , simple service work repairs etc , I wonder if I might ask a silly question ( did lots of machine rebuild work in my work life pumps , clutches winches and all manner of marine paraphernalia ) are you saying that the gearbox bearings on my gsa are likely to be sealed units even although the gearbox is in an oil bath of G/Box oil ?
 
Exactly that, there are three shafts so six bearings. Each bearing is double-sealed eg a rubber lip seal fitted to each side. This is to prevent microscopic debris such as wear particles in the oil from entering the bearing and embedding into the surface which leads to premature wear and eventual failure.

I’m also a Marine Engineer by trade myself, not a motorcycle tech.
 
Finally got the new input shaft from my local Motorrad dealer after over three weeks of waiting. Good luck to anyone else waiting on spares from Germany.
 
Bike reassembled and test ridden, all good. I had to wait for a new rear master cylinder as the old one was weeping. The bike rides better than ever, all backlash seems to have gone it’s super smooth now on and off throttle. A little gear rattle in neutral when hot which I now think is output shaft first gear needle roller bearings but it is so minimal I can live with it, it was deafening previously due to excess end float.

Just the faulty heated grip and tyre pressure sensors to fix and the LED headlight cluster to fit and it’s all systems go.
 
Nippy Normans supply Touratech, Wunderlich, Desert Fox and many other makes of accessories.
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