Author Topic: An Odd Place for Oil Seepage  (Read 6198 times)

Offline kris

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An Odd Place for Oil Seepage
« on: April 19, 2015, 07:45:20 PM »
Hi folks,
I noticed this little bit of oil where the tranny meets the bell housing. Has anyone seen this before?

Thanks!
  • In the Hammer!! Hamilton, Ontario, Canada
  • 1986 K100RT (Heinz) 2004 Kawasaki Concours (Eddy) 2007 Moto Guzzi Breva 1100 (Linda) Previous: 1968 Honda CD175 1973 Kawasaki S2350 1975 Honda CB550K
"I got bike fever bad!!"

Offline orforester

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Re: An Odd Place for Oil Seepage
« Reply #1 on: April 19, 2015, 08:03:09 PM »
Bad rear main seal, probably some oil underneath as well??
Bob
1989 K 100 RS se (SOLD)
1985 K 100 RS, now RT
1979 XS 650 Yamaha Street Tracker
2008 R 1200RT

Offline Snowman

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Re: An Odd Place for Oil Seepage
« Reply #2 on: April 19, 2015, 08:16:14 PM »
Yeah, the only place back there that leaks oil is the rear main seal.
1993 BMW K1100LT
1985 BMW K100RS Turbo
2009 Moto Guzzi Norge
1986 Suzuki GSXR750, GSXR1100, GSXR50

Offline kris

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Re: An Odd Place for Oil Seepage
« Reply #3 on: April 19, 2015, 08:55:03 PM »
Shit. I replaced this seal. Must have screwed it up!!!
  • In the Hammer!! Hamilton, Ontario, Canada
  • 1986 K100RT (Heinz) 2004 Kawasaki Concours (Eddy) 2007 Moto Guzzi Breva 1100 (Linda) Previous: 1968 Honda CD175 1973 Kawasaki S2350 1975 Honda CB550K
"I got bike fever bad!!"

Offline kris

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Re: An Odd Place for Oil Seepage
« Reply #4 on: April 19, 2015, 08:57:50 PM »
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....
  • In the Hammer!! Hamilton, Ontario, Canada
  • 1986 K100RT (Heinz) 2004 Kawasaki Concours (Eddy) 2007 Moto Guzzi Breva 1100 (Linda) Previous: 1968 Honda CD175 1973 Kawasaki S2350 1975 Honda CB550K
"I got bike fever bad!!"

Offline pallum

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Re: An Odd Place for Oil Seepage
« Reply #5 on: April 19, 2015, 09:04:25 PM »
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.
  • Federal Way, WA
1994 K75RT 45,000 miles (Apr 2020)

Offline kris

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Re: An Odd Place for Oil Seepage
« Reply #6 on: April 19, 2015, 09:15:36 PM »
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??
  • In the Hammer!! Hamilton, Ontario, Canada
  • 1986 K100RT (Heinz) 2004 Kawasaki Concours (Eddy) 2007 Moto Guzzi Breva 1100 (Linda) Previous: 1968 Honda CD175 1973 Kawasaki S2350 1975 Honda CB550K
"I got bike fever bad!!"

Offline kris

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Re: An Odd Place for Oil Seepage
« Reply #7 on: April 19, 2015, 10:33:44 PM »
Do those breathers require any kind of servicing? Does anyone know?

The learning continues!
  • In the Hammer!! Hamilton, Ontario, Canada
  • 1986 K100RT (Heinz) 2004 Kawasaki Concours (Eddy) 2007 Moto Guzzi Breva 1100 (Linda) Previous: 1968 Honda CD175 1973 Kawasaki S2350 1975 Honda CB550K
"I got bike fever bad!!"

Offline kris

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Re: An Odd Place for Oil Seepage
« Reply #8 on: April 19, 2015, 10:34:48 PM »
Do those breathers require any kind of servicing? Does anyone know?

The learning continues!
  • In the Hammer!! Hamilton, Ontario, Canada
  • 1986 K100RT (Heinz) 2004 Kawasaki Concours (Eddy) 2007 Moto Guzzi Breva 1100 (Linda) Previous: 1968 Honda CD175 1973 Kawasaki S2350 1975 Honda CB550K
"I got bike fever bad!!"

Offline Motorhobo

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Re: An Odd Place for Oil Seepage
« Reply #9 on: April 20, 2015, 06:44:07 AM »
There's the clutch pushrod seal but then it would smell like gear oil, not engine oil.
1994/1995 K75 ABS Frankenbike: original engine 136k miles, frame from Gary Weaver (RIP), 173k miles -- Current Odometer: 193k miles
1994 K75 since 2013, 76,000 mi (11k mine) w/California Sidecar Friendship II Sidecar & Black Lab 'Miss B'

Past: 1974 Honda 550/4 (first bike), 1994 K75 (sold), 1995 K75 ABS (parts bike), Sidecar Dog & Best Bud 'Bo' - RIP

Offline rbm

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Re: An Odd Place for Oil Seepage
« Reply #10 on: April 20, 2015, 10:11:11 AM »
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.
  • Regards, Robert
Toronto, Ontario

1987 K75 - Build Blog @http://k75retro.blogspot.ca/

Offline Freelancer

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Re: An Odd Place for Oil Seepage
« Reply #11 on: April 21, 2015, 12:44:12 AM »
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
1991 K100RS

Offline kris

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Re: An Odd Place for Oil Seepage
« Reply #12 on: April 29, 2015, 08:14:51 AM »
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.
  • In the Hammer!! Hamilton, Ontario, Canada
  • 1986 K100RT (Heinz) 2004 Kawasaki Concours (Eddy) 2007 Moto Guzzi Breva 1100 (Linda) Previous: 1968 Honda CD175 1973 Kawasaki S2350 1975 Honda CB550K
"I got bike fever bad!!"

Offline rbm

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Re: An Odd Place for Oil Seepage
« Reply #13 on: April 29, 2015, 02:39:06 PM »
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).
  • Regards, Robert
Toronto, Ontario

1987 K75 - Build Blog @http://k75retro.blogspot.ca/

Offline kris

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Re: An Odd Place for Oil Seepage
« Reply #14 on: April 29, 2015, 03:27:34 PM »
Thanks Robert
  • In the Hammer!! Hamilton, Ontario, Canada
  • 1986 K100RT (Heinz) 2004 Kawasaki Concours (Eddy) 2007 Moto Guzzi Breva 1100 (Linda) Previous: 1968 Honda CD175 1973 Kawasaki S2350 1975 Honda CB550K
"I got bike fever bad!!"

Offline lilau3

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Re: An Odd Place for Oil Seepage
« Reply #15 on: July 25, 2018, 07:23:31 AM »
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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  • Australia - Melbourne
  • 1988 BMW K100 LT, Vespa GTS300

Offline billday

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Re: An Odd Place for Oil Seepage
« Reply #16 on: July 26, 2018, 10:15:39 PM »
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.
  • New York State, USA 10977
  • 1985 K100

Offline Chaos

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Re: An Odd Place for Oil Seepage
« Reply #17 on: July 26, 2018, 10:25:42 PM »
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!
  • sw ohio
1987 K75S    VIN 0231
Original owner, Original litter
200,000 miles (plus or minus) and 5 paint jobs
2012 Ural 2WD sidecar (BMW's bastard step child)

Offline lilau3

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Re: An Odd Place for Oil Seepage
« Reply #18 on: July 26, 2018, 10:38:47 PM »
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.







  • Australia - Melbourne
  • 1988 BMW K100 LT, Vespa GTS300

Offline lilau3

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Re: An Odd Place for Oil Seepage
« Reply #19 on: July 26, 2018, 10:42:43 PM »
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.
  • Australia - Melbourne
  • 1988 BMW K100 LT, Vespa GTS300

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