Last question, rear main seal, i promise!
 

bike is torn apart, getting ready to install the seals and the two seals i pulled out are the same depth, the two seals i received from chicago bmw according to the parts fiche are not. the "outter" seal is "thicker" (depth wise) than the one i pulled out, it goes further into the crank case and would seem, from a quick observation, to block the top breather hole.

new outter seal part number (this is the "thicker one"): 11111341087

new inner seal (this one seems to be correct, or at least the same as the one i pulled out) part number:
11111341135

did BMW update the seal since 99'??? i'd hate to install a thicker seal and have it not be right 10 hours of labor after the fact. please advise, thanks!

Im interested in this.

IIRC Dr Ramjet answered this same question some time ago. No I don't 'member the answer...I'm old.

here is a picture of the 2 seals, the one on the left is the new one, the one on the right is the one i removed (somewhat hamfistedly). the inner sealing portion that touches the crank seems to be at the same level, but the new one has roughly 3mm more material protruding out towards the back of the clutch carrier.

http://www.retr0.com/dkhirons/seals.jpg

I don't have the exact info on this but it would seem that the seal is an improvement rather than a whole new set up. The main thing to watch for is that the inner seal does not block the venting between the two seals. If you can see the hole is not blocked when the inner seal is bottomed out then all should be good. The new seal definitely looks like a better design than the old one.

the inner seal is fine, i'm concerned this new outter one, if inserted flush with the outside of the engine case, will block this hole, due to its thickness. what i was considering is pushing the seal in as far as a 7mm seal would go and just leaving a few mm's exposed outside the case. i can't see it hurting as long as there is no contact with the clutch carrier.

Oh, I was assumining this was the inner seal. I haven't been in there yet myself. Sounds like you are on the right track though. Can you tell by the clutch parts if there will be an interference issue with the seal? If not, then that would probably be the right solution. Is there any type of sealant recommended for the outer seal installation? It looks like the new seal has a better seal and grip on the od over the old seal anyway. Hopefully someone with direct knowledge of these seal differences will chime in before you have to button it up. I know I wouldn't be able to stop thinking about it unless I knew for sure too.