03 k1200rs final drive oil change pictures

Just drained my final drive oil to examine after buying and researching service history. Service notes stayed might need to replace final drive crown bearing, but nothing more. So, these are the pics of the oil I just drained out. Because I'm new to this bike and BMW's, are these particles indicating a failing/worn final drive? I'm thinking the very small flakes in the pan say probably, but with my lack of experience, do t know. What are your thoughts after looking at pictures?

Replace the bearing! You don't want the bearing failing on the road.

I have rebuilt over 100 of these final drives & that one needs to be rebuilt.

If those are metallic flakes in the oil, you should have that drive rebuilt while you might still get by with bearings and seals replaced and a proper re-shimming. Pressing the point by continuing to ride it might cause damage to ring and pinion.

I’ve had two of these for my sidecar rig rebuilt by Tom Cutter at Rubber Chicken Racing Garage in PA—the OEM and a used spare. The rebuilt OEM unit is still going strong in the SC rig after 25k+ miles so haven’t needed the spare.

Best,
DG

Hard to tell from the pics if there really is an issue but, you got the $$ and the time and want to be safe.............................

In the HD trade exam, there is a question regarding the exact same as posted in the pics. The correct answer is if there is no complaint, drain the oil and refill and check again at next service interval.

Final drive

Since I have the FD I picked up on Ebay, it seems like that would be the easiest for right now, then maybe have the original rebuilt at my convenience?

Thoughts..

bubbadozer1 said:

Since I have the FD I picked up on Ebay, it seems like that would be the easiest for right now, then maybe have the original rebuilt at my convenience?

Thoughts..

Click to expand...

No guarantee the ebay unit is any better.......

My understanding of the rear drive failure mode is that the bearing cage breaks, allowing the balls to sink down in the vertical races. With the balls all gathered at the bottom, the rear hub and wheels are no longer properly supported and positioned. Their movement exceeds the seals' abilities, so the first sign (if you don't notice the free play in the wheel) is that the fluid gets past the seals, onto the flange of the rear wheel. Eventually the whole wheel/hub assembly flops over from vertical.
Looking at your drain plug photo, I didn't see enough metallic crud to think your unit was on its way out. The photo of the used oil may be different story, but it's hard for me to tell.
If replacing or rebuilding is not too big a burden for you, you might be wise to play it safe and do so, especially if about to embark on a trip. But without knowing more of the bike's history (when was the rear drive last flushed?) I might be tempted to let it go awhile.

JeffDiCarlo said:

My understanding of the rear drive failure mode is that the bearing cage breaks, allowing the balls to sink down in the vertical races. With the balls all gathered at the bottom, the rear hub and wheels are no longer properly supported and positioned. Their movement exceeds the seals' abilities, so the first sign (if you don't notice the free play in the wheel) is that the fluid gets past the seals, onto the flange of the rear wheel. Eventually the whole wheel/hub assembly flops over from vertical.
Looking at your drain plug photo, I didn't see enough metallic crud to think your unit was on its way out. The photo of the used oil may be different story, but it's hard for me to tell.
If replacing or rebuilding is not too big a burden for you, you might be wise to play it safe and do so, especially if about to embark on a trip. But without knowing more of the bike's history (when was the rear drive last flushed?) I might be tempted to let it go awhile.

Click to expand...

I have examined several drives at different stages of failure. Jeff is right in the observation of the totally failed drive but the explanation is not exactly correct. The failure mode starts with a slight fracture in the thin hard surface of the inner or outer race of the big ball bearing. The fracture is most often caused by the bearing going metal-to-metal to hard or too often. The fracture soon turns into a chip, leaving a pit in the race. Now as the balls come around and hit the little pit the balls are damaged. Soon the damaged balls are further damaging the races. Eventually one of the balls will jam in a pit and the rest of everything comes around and like a train wreck the balls jamming together destroy the cage and all the balls wind up on one side of the bearing. The earliest sign of failure is the detection of a solid little steel flake broken off the damaged race. You might also see a lot of gray metal sludge which is material worn off the balls.

By the time the cage breaks and the little bearing "train wreck" happens you don't need to examine drained oil to know it broke.