which way does the swing arm bearing go?

[TommyT]

Started a clutch spline lube about two weeks ago on a 1990 K75 RT, when taking off the swing arm the left side bearing was in pieces. It took two weeks to get the bearing from Max. Now that I look at it I am not sure which side should face out. See the pictures and vote, vote often!
20200503_195705.jpg (19.32 kB . 768x432 - viewed 573 times). I think the side with the black ring faces in, see below.

[triplek]

Black ring out.

[triplek]

You may also want to consider removing the black ring (dust cap) and then remove the seal beneath it - and greasing the bearing with a very good grease.

You will be able to pack far more grease into it then the factory.  If you do remove the dust cap and seal use a very flexible wire like pick tool and take your time working around the seal to remove it without deforming it.

If you add grease it's usually best to remove the old grease unless you know that your grease is compatible.  Emphasis on "you know".

[triplek]

I should also add that if you do repack it with a grease of your choice you can grease the bearings as part of routine annual or biannual maintenance and they will last...forever.

[Laitch]

The bearings are new and they're sealed. Leave them alone and move on. You'll probably sell the Brick and buy a Zero before they need lubing.

From Clymer.

[TommyT]

Thanks all.

It looks like a landside, voters say, black side out.

[Laitch]

. . . voters say, black side out.

Not quite. I just follow the manual in my unimaginative way and try not to complicate things. Between Clymer, Haynes and the BMW workshop manual an answer can usually be found.

[triplek]

I think those are shielded not sealed,  but I certainly don't disagree that they will last donkey years (a very long time indeed) with just the factory grease pack.

Greasing them is pretty easy and should be done with some regularity. They're not standard sized and may become increasingly hard to find in the future. As it stands now they are already priced between 45 and near $90 each for something that in near similar sizes often sells for 10-$20 each.

I expect that in the not too distant future people will commonly be shimming in shorter bearings as the stock size becomes pricier and rarer.c

[Laitch]

I think those are shielded not sealed,

From MAX BMW

[triplek]

I think he's got a Mahle bearing, not the FAG from Max  ;)

And also; you can literally see the bearings on the obverse of the plastic shielded side.

Max it my opinion aside, there is a technical listing somewhere that will spell out all of the properties for this bearing right down to defining by recognized engineering standards whether it's shielded, sealed or other.   

Until then, I suppose that Max's ad copy is the best source available and definitely outrules my opinion. No problems with that.

[TommyT]

I did get the bearing from Max and does look like a sealed bearing.

[Laitch]

Until then, I suppose that Max's ad copy is the best source available and definitely outrules my opinion. No problems with that.

I'll defer to you so you can focus on getting your ride rideable.