Balance shaft rear seal

[alex_rsa]

Hi,

The seal on my balance shaft is weeping as I am changing the clutch I thought I would change it as well.

I realise i can get is from BMW or other BMW part suppliers but at close to £20 for just a seal I was hoping someone had found (and used) an alternative.

The seal I need is number 10 in this picture for a 2004 bike:
https://www.maxbmwmotorcycles.com/fiche/DiagramsMain.aspx?vid=51556&rnd=07012015

The diagram lists the seal as 20x37x7. There are lots of places listing seals for sale but I am not an expert on what would be an exact match.


Thanks

Alex

 

[Bendy toy]

I would get advice from a bearings factors. Last time I found an alternative supplier they said the OEM seal was cheap quality. They offered a double lip type for only a couple of £s. It was for the engine front cover.

Also consider changing the back end crank seal while the bike is open and the gearbox seals if they are not integral to the bearing.

 

[Pukmeister]

Whilst it's apart, burnish the input shafts splines with some molybdenum disulphide grease and an old toothbrush. Be sure to wipe away excess grease before reassembly.

 

[Canuck]

I've just done this but bought the seal from bmw. Me reasoning was that for the sake of saving a tenner, I might as well buy the eom seal as it sure is a lot cheaper than another clutch replacement if it fails. Although perhaps bendy is on to something.,, I gather the seal in question fails regularly (I'm on an 08 model though so different seal) so perhaps something better would be a smart
idea.

 

[alex_rsa]

Well after looking into radial shaft seals only 2 types seems available in 37x20x7. R21 and R23 and the only difference is an extra lip. Also the size seems rare and there is not much choice in manufacturers. The seal is also lower quality nitrile(?) rubber.

The later bike 2008+ have a different size and they are available in a higher quality vitron seal - probably why they changed....

So ordered both type of seals (R21 and R23) for £4 delivered.

 

[Bendy toy]

I put a new seal into my newly painted engine front cover.
It leaked after a couple of weeks.
I pulled it out with the self tapping screw method and found the inner seal lip had got folded over.
The replacement went in nicely and was dry the last time I looked.


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