Much appreciated info, guys!  I'm off in search of the spring-type seal today.  That will be a known item, and I'm less likely to need three of 'em! Thanks.  

Just to close the loop here on a thread (and task) that has gone on too long -- I used Charlie99's method to replace the oil seal with the timing chain cover in place. I drilled three holes around the seal's perimeter, screwed in some longish thin sheet metal screws and it popped right out.  A bit of grease on the drill helped keep track of the dust and swarf so there was little mess involved.  Actually, the three screws were overkill, as a little tug on the first one did the trick.  I tapped the new seal in with a socket and all seems well now.
As an aside, the OEM seal was odd in that there was no spring around the lip to keep it snug as it wore in service.  It was also made of brittle plastic, as opposed to the new seal, which is rubber or a very pliable plastic material.  
I decided against using the newer Teflon seal, reasoning that I'd be better served with what I'm accustomed to.
Thanks again for the help as I bumbled through this.

Good job on getting it done!.

If the OEM seal wasn't otherwise damaged, then the absence of the spring suggests it was a teflon lipped seal.

Did your replacement have a spring?

Mike

brickrider2 wrote:I decided against using the newer Teflon seal, reasoning that I'd be better served with what I'm accustomed to.

Did you use the old-style OEM seal or an aftermarket equivalent?

I acquired a non-OEM seal from a known US supplier. It was made in Taiwan and seems to be as good as any others I'm used in the past.  The seal I removed has no spring, as I noted above.  If it is Teflon it is like no other Teflon I have seen.  It is not slippery and not very pliable.  It is marked BMW. To be honest, it seems to be a piece that was selected by the bean counters, as opposed to the engineers of the company.

What's the brand, part number and source? Others might be interested.

Such seals are typically ordered by their size.  From memory, it is 36x52x7 mm.  The box said Federal Mogul (?) but that shouldn't be seen as terribly significant.  Years ago I worked at a business that rebuilt engines.  We routinely put suppliers' parts in boxes with our firm's name. I bought the oil seal in question at a nearby auto parts store.  It was a special order item but, apart from a few days waiting, there was no problem getting it.  Of course, that may not be true of all BMW parts.

brickrider2 wrote:From memory, it is 36x52x7 mm.  The box said Federal Mogul . . .

If it's this one, that's a significant price savings. Please let us know how it all works out.

The timing cover on my K1100LT has started leaking once again.  This time the leak is on the lower right side.  When I purchased this machine the inside of the faring showed evidence of a oil leak there.  Before I make a gasket for that application, I'd like to verify that the engine area on the other side of that cover should not be pressurized.  Having tried and failed a number of times to seal that cover, I am now wondering if a crankcase vent somewhere is plugged.  Perhaps I'm grasping at straws at this point, but I cannot for the life of me understand why that cover cannot be made oil tight on my bike. 

BR get a flat sheet of glass. Apply a very light smear of bearing blue to the cover, with the cover face up place the glass on the cover and observe the sealing surface. It should be even. Or alternatively apply a smear of fine lapping paste to the sealing surface and lap the cover on the glass in a figure of 8 pattern. If the cover is flat the lapping marks will be on all of the sealing surfaces.
Regards Martin.

or use the 3-Bond 1184 instead of that 1209  Amazon 1184

I owned one of the best oil leaking bikes you could possibly get, a BSA. And it didn't leak or weep a drop after surfacing the cases and using Hylomar sealant.
Regards Martin.

another fine urethane based sealant Hylomar Blue  Amazon Blue

An old trick that I learned long, long ago from a friend who owned a couple of mid 60's Triumphs was to take a piece of sewing thread and lay it into the sealant smear all around the joint just before you assemble the cover.  The idea is that when all else fails, the thread will prevent the leak from pushing through the sealant.

He told me that it was a trick used by aircraft mechanics during WWII that he learned from his uncle.

I've heard of a variation of the cotton trick except it was fishing line. I've never had to use it.
Regards Martin.

I like the idea of laying a thread in the sealant.  It makes intuitive sense to me.  
I've been mulling over this problem and in particular the suggestion for checking the cover for warping using a pane of glass.  I can foresee some issues with that.  The cover is quite wide and exceeds the size of any abrasive paper that could be used to true it up, if necessary.  That being the case, I'd be challenged to make the sealing surface true a portion at a time.  
A second doubt I have is the actual quantity of Dri Bond.  I've always used such goop sparingly to avoid the excess being squeezed out and finding it's way into oil passages.  Maybe I'm too cautious in that regard. Is a bead 4-5 mm thick a reasonable and safe amount of goop?  What should I be aiming for here?

I think a bead 4-5mm wide is a bit excessive.  I like to put enough down to create a uniformly opaque film when I spread it with my fingertip.  When you put the cover together the seam that the sealant is filling should only be a couple thousandths of an inch or 0.05mm.  I've seen video of the assembly of engines at the factory and the robot that applies sealant lays down a bead that looks to be about 1.5mm or about a 16th of an inch.

I continue to prove my near-complete lack of mechanical ability.  
When I had a second look at the HES I noticed oil.  The gasket on the T-shaped ignition cover was wet enough to make me think the "leaking timing cover" could quite possibly be oil tight! Oil from the crank seal flows down the leg of the cover and exits near the seam of the t-cover and engine block, making it appear the cover is the culprit.  
I have twice replaced the crank seal and failed to stop the leak.  I've decided the "conventional" oil seal is a waste of time. I don't seem to be able to make the seal with the spring around the lip work in this application.  I used an appropriate sized socket to tap it home, but what has worked in the past doesn't in this case. I have ordered the other style crank seal from the BMW dealer.  (BTW, that style seal is also offered by EME.)
While waiting for it to arrive I'll study the suggestions for using a film canister to aid installation.  
I wonder how many practice installs I'll need to make for this to work as it should.    Perhaps I should have ordered two of the new seals from the git go.

Use a silicon ('brake') grease to lubricate it, inside and out, before trying to fit it.

BR have you checked the seal running surface for pits and marks, you'll also need to linish the seal running surface.
Regards Martin.

In the course of oiling the shaft in preparation of installing the present seal I didn't find any scoring that might defeat the seal, but I'll have another look.  I've been know to miss the obvious!
Martin I don't understand your suggestion to "linish the seal running surface".  Can you explain that again? I assume the edge of the new seal's lip will be feathered and ready to go to work.  Isn't that a realistic assumption? 
Thanks.

[size=36]Linishing.[/size]
Linish is an engineering term that refers to the process of using grinding or belt sanding techniques to improve the flatness of a surface. The flatness may be two-dimensional, i.e. with the view of achieving a flat plate, or one-dimensional, e.g. with the view of achieving a perfectly cylindrical shape.


Just don't grind away too much metal! 

Seals can make a track or mark where the lip has been previously been running. You need to use very fine wet and dry paper to take these marks out. You will need to work your way around the shaft evenly removing the running marks.https://www.tritec-ps.com/the-importance-of-seal-running-surface/ and https://www.plantservices.com/articles/2002/423/
Regards Martin.

Thank you gentlemen, for the clarification.  I am familiar with the task, I just was not up on the terminology.  In fact, cleaning up the shaft of the H2O/oil pump was probably the step that (finally) got the pump oil and water tight. I'll have a good go at the end of the crank shaft before I put another seal in there.

Martin, the link to the seal manufacturer that you so kindly provided is appreciated.  Interesting info there, and some counter-intuitive recommendations as well. I note the Teflon seals are best installed dry.  That will make the job a bit more tricky, I'm sure.  However, it's worth the effort to set that seal properly and then be able to forget about it for a good long while. Thank you, Martin.

Next chapter in the shade tree mechanic v. crankshaft seal saga is behind me.  First, the sad history.  I struggled to seal the timing cover, but finally got it oil tight.  Then, the  oil seal behind the HES began to leak.  I tried unsuccessfully twice to install the poly (?) seals with the spring, erroneously thinking I should stick with the familiar rather than use the PTFE seal that came standard with the bike in 1995.  In the end, I needed to use the PTFE seal.  I wasn't able to find a pill bottle of suitable size to help set the seal's lip in toward the crankshaft; neither was I able to use a bit of 35 mm film as a guide.  What did finally work for me was a lowly popsicle stick that I reshaped with a fine file.I pushed the seal on the shaft and at the point where the lip folded back toward me I used my wooden tool to reorient it inward. 
I've since ridden the bike about 200 miles, long enough to disclose a leak.  Everything is dry down there