An Odd Place for Oil Seepage

[kris]

Hi folks,
I noticed this little bit of oil where the tranny meets the bell housing. Has anyone seen this before?

Thanks!

[orforester]

Bad rear main seal, probably some oil underneath as well??

[Snowman]

Yeah, the only place back there that leaks oil is the rear main seal.

[kris]

Shit. I replaced this seal. Must have screwed it up!!!

[kris]

I will check underneath. Don't believe I saw anything under there...but I wasn't looking that hard. I'll have a look. I can live with it until I can muster the initiative to rip it apart again....

[pallum]

I've seen the same thing on my bike for a few months now. Alternator shaft seal seems dry, but the transmission breather certainly does not. Also occasionally when opening the transmission fill port a rush of compressed air comes out. I'm fairly certain its some crud in that breather that every once in a while spews out some oil. I still have yet to 100% confirm it but I haven't been bothered enough to.

[kris]

Thanks Pallum. I checked my tranny fluid level tonight. All good. Swapped out some fluid for some Guard Dog 421 moly.  No rush of air. I'm not sure my gearbox is 100 per cent. Sounds a little rattly on the take-off. Good after that. Motor purrs like a kitten....truly. What a sweet engine (K100). I'll keep an eye on levels and check underneath for signs of leakage in the bell housing. I'll be a little pissed if I pooched the rear main install....but it's not like I'm a mechanic!! We live and learn, don't we??

[kris]

Do those breathers require any kind of servicing? Does anyone know?

The learning continues!

[kris]

Do those breathers require any kind of servicing? Does anyone know?

The learning continues!

[Motorhobo]

There's the clutch pushrod seal but then it would smell like gear oil, not engine oil.

[rbm]

That leak location is not a normal place that would signal a main seal leakage.  Normally, oil would come out the weep hole on the bottom of the transmission.  I would hazard a guess at it coming from the area around the starter motor or from behind the alternator dog driver.  It could be the O-ring on the starter is worn or the seal around the alternator drive shaft.  Since you had to remove the starter to do the main seal replacement, look there first.

[Freelancer]

Could you have spilled some gear oil? Left over parts cleaner?
You said that you had it apart recently. :dunno

One real possibility could be your fuel tank breather hose/overfill cup or line. Mine has slipped off before and by the time the gas made it to a place it could be seen, it had collected a lot of oily grime residue.

Just an idea

Later,
Freelancer

[kris]

I pulled the alternator yesterday and it appears that bit of oil seepage is coming from the alternator drive. It is very minor and I'm not going to get into tearing it apart right now. I fiched the assembly (maybe not quite thoroughly enough) and can't quite tell if there is an O ring or other type of oil seal there. It's not really bothering anything.

[rbm]

No O-ring, just an oil seal.  You'd have to remove the bell housing and the alternator drive assembly from the housing to get access to the seal.  It's probably not worth it until you have to tear into that section of the engine (at some point in the future).

[kris]

Thanks Robert

[lilau3]

I have just had a significant leak in this place. Just ordered a new scrotator drive seal (BMW: 11 14 1 461 185). Plus it need the 14mmID x 1.6mm o-ring on the end of the shaft replacing.

Hopefully the seal will seat itself just by tightening the scrotator drive bolt back up.


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[billday]

Am I a bad person?  If I saw an oil stain like that, I'd just  say, Hmm,  another thing to not clean,  guess I'll go for a ride.

[Chaos]

Am I a bad person?  If I saw an oil stain like that, I'd just  say, Hmm,  another thing to not clean,  guess I'll go for a ride.

Ditto.  First, don't look for leaks, and 2nd, if you do see one, check sightglass to see if sump still has some oil.  If so, no prob!

[lilau3]

Am I a bad person?  If I saw an oil stain like that, I'd just  say, Hmm,  another thing to not clean,  guess I'll go for a ride.

Yes. Yes you are a bad person.  :nono

Kidding, each to their own I suppose. I'm not a big fan of oil dripping onto the exhaust, gets a bit smokey after a while.

Great thing about 'nakedizing' the bike is everything is fairly accessable now so didn't take much to get the battery/starter/alt out. Bit of degreaser and that area is looking all shiny and new now (oh the satisfaction!). My tip if you have to clean up this area is remove the alternator driveshaft seal, plug it with a bit of tape or something, put it back in, then go to town with the degreaser without worrying about getting crap in the bearing behind.

From what I have read leaks in this area are not common. Judging from all the crud accumulated in the area it looks like it's been leaking there for a while though. The rubber on the seal was very hard so it's not suprising.


I'll update on sucess or not once the new seal is in and it's all put back together.

[lilau3]

Ditto.  First, don't look for leaks, and 2nd, if you do see one, check sightglass to see if sump still has some oil.  If so, no prob!

I still need to get a 'Roadworthy Certificate' to get this bike on the road, something we have to do in this state. They don't allow significant oil leaks so basically I have no choice but to fix it.