[CharlieVT]

A forum member messaged me a while back asking about a preemptive rebuild of his early model K1200LT Final Drive. Some time later, he emailed to say he was starting to see some metal flakes in his FD lube. So he shipped me his FD and I just finished the rebuild.

Good catch :thumb:

Pretty severe pitting of both inner and outer crownwheel bearing races. I suspect that the retainer (cage) would have failed pretty soon leading to destruction of the seal and loss of FD lube. This FD had a 0.70mm preload shim. My calculations for the replacement bearing indicated a 0.50mm shim. This suggests that the original bearing was over shimmed by 0.20mm

Inner race pitting:

Outer race pitting:

 

[ErnieA]

Did this member state how many miles he put on this drive with the preload that tight?

 

[deanwoolsey]

As always Curtis, thanks for the insight.

 

[RealWing]

Looks like typical bearing fatique/spalling damage due to overload. Good picture of early failure damage, but like Curtis said - it will progress very quickly to severe damage.
Good catch.

 

[CharlieVT]

Did this member state how many miles he put on this drive with the preload that tight?

I just checked my info on this FD and I don't have the mileage.
Maybe he'll tell us....

 

[dpittman]

Thanks again Curtis for your help. The FD is off a 2000 model and at the time of removal it had a little over 48,000 miles on it.

 

[Pedro]

An interesting survey I found on a BMW sports bike forum about final drive failures is http://www.i-bmw.com/showthread.php?t=19534