Hey folks!
Yesterday i made a full service of my K100 RS- 85 (ca 125.000 kms), and, as usuall, when changing the final drive oil, the lower drain bolt is stucked full of some strange kind of (magnetic) metal cuttings. The stuff is flat and shiny, like a cheap (bad) layer of chrome that falls off, but smaller and thinner.

What can this be, and is it usuall for this kind of final drive? Ive had the bike since 2003 with the same problem, but it still works like a charm...

The oil is somewhat "milky" in comparence to the gearbox oil (but not much enough to scare me), the final drive has been serviced at some point by the previous owner.

Suggestions anyone?

Thanx/ Örjan

Hi there,
the reason why the screw is magnetic is that you'll always get some abrasion of metall from the final drive (same for the gear box). The magnetic screw collects them to ensure a well lubricated final drive. If the particles are small, there is no need to worry. Smear them between your fingers. The feel a bit grainy, but not much. They look much bigger on the magnetic screw, than they really are (looks like a little x-mas tree). There is not supposed to be any big splinters caught on the screw, like it happened to me this spring (I already fear the sight of my final drive)...
Hope that helped...

Thanx for answer! Yes, thats about what i get on the magnetic bolt, a really large amount of "sticky" metal flakes, very thin and not harmfull looking. But i cant figure out why and from where this stuff comes?? The gearbox magnetic bolt is almost clean, while the final drive looks like a christmas tree, and it keeps coming for each time im changing the oil.

At some point the "flake- source" must run dry and have made a huge hole somewhere..? As long as the rear wheel dont fall off, im satisfied i guess...

/ örjan

Have a look here and here. Unfortunately BMW did not put up the greasing of the splines in the maintenance, but you better do it once in a while (every 2 years maybe)...