Vintage BMW Motorcycle Owners

Hello all,
A small drop of oil at the small hole near the drain plug of my R50/2.
I know this is a special channel to keep leaking oil away from the break linings.
But I understand this channel evacuates the leaks from the big seal, the one close to the wheel. But could it be also the small seal in the housing ?
It looks like the leaks from this small seal goes back inside the spacer and drop inside the wheel hub ?
Any one knows ?

Laurent.

Yes, you are correct Laurent-
The small drain hole on the bottom of the housing (next to the oil drain plug) drains oil from the collection reservoir in the ring gear cover.
That reservoir gathers any oil that may leak past either the large or small ring gear oil seals; the purpose being, as you say, to protect the brake linings from contamination.
Oil getting past the large seal falls directly into the reservoir, oil getting past the small seal on the opposite side of the ring gear migrates back to the reservoir via the spacer tube, ring gear hub splines, wheel hub splines, and then drops into the reservoir.
The other possibility for oil dripping from the small drain hole, besides worn seal(s) is way too much oil in the housing; either by accidental over-filling, or by oil migration from the swingarm/driveshaft past the pinion seal.
Best-
George

Wow ! Very good design.
So I just have to remove the wheel to see if the inner side of the ring gear is oily. If it is, the small seal is faulty at least.

Laurent.