Author Topic: Milky gearbox oil  (Read 279 times)

Offline Huwj29

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Milky gearbox oil
« on: August 27, 2019, 12:19:55 PM »
Got my first K100RS 8v 1986 a few months back and have not ridden it as been tidying it up.
Found the clutch boot had split so just ordered another one this morning, but also found my gearbox oil was milky!
So 2 questions,
1, whats the best way to flush the oil milky oil out.
2, what is recommended to go in the gearbox? Is it EP90?
  • Plymouth
  • 1986 K100RS

Offline johnny

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Re: Milky gearbox oil
« Reply #1 on: August 27, 2019, 02:04:44 PM »
greetings...

are you in plymouth wisconsin usa...

poast some photos so we can see what you see...

j o
  • :johnny i parks my 96 eleven hundert rs motobrick in dodge county cheezconsin  :johnny

Offline Laitch

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Re: Milky gearbox oil
« Reply #2 on: August 27, 2019, 02:19:29 PM »
If you have a Plymouth, what year was it made? I sat in a 1952 that had a push-button transmission but the used car dealer couldn't start it so I eventually bought a Honda CL77.

Have you already drained this milk? It's transmission oil combined with water created by condensation diluting the oil. It was caused by temperature changes during storage and disuse. If it has stopped draining out, replace the drain plug.

EP90 is one of BMW's recommended fluids. Use it if you've got it. I use 80W90 to accommodate temperature swings in fall. Others here use Redline, Red Devil, Red Menace and a host of other multigrades that deliver—or promise to deliver—improved performance and increased self-worth. You could choose from one of those. Another choice is to refill the transmission, run the moto, drain it, refill it, run it, drain it, refill it, run it, drain it and repeat the process until you believe the transmission contains fluid the quality of mother's milk. No harm in that. Regardless of what course you decide to take, once new fluid has replaced the old, any water remaining in the case will evaporate during use if you actually use the moto instead of ruminating interminably about it like so many here seem to do.

Don't overfill the transmission. The oem rear strut wrench has a mark on its handle that allows it to act as a dipstick to measure oil up to the appropriate level; otherwise, fill with BMW's recommended volume of oil.
  • Along the Ridley in Vermont.
  • 1995 K75 72,000 miles
I wept because I had no radials until I met a man who had no splines.
http://www.motobrick.com/index.php/topic,296.msg53303.html#msg53303

Offline Huwj29

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Re: Milky gearbox oil
« Reply #3 on: August 28, 2019, 03:42:33 AM »

[more]
No Plymouth UK
See attached pictures. The clutch boot was in pieces so should I assume this is the reason for the milky oil.
Also I have a drip (one drop over night) from the hole in the bottom of the bell housing. Is this something I should be concerned about?
Is this oil ok for the gearbox


greetings...

are you in plymouth wisconsin usa...

poast some photos so we can see what you see...

j o
  • Plymouth
  • 1986 K100RS

Offline Huwj29

  • Motobrick Curious
  • Posts: 14
Re: Milky gearbox oil
« Reply #4 on: August 28, 2019, 03:44:05 AM »
See attachment
  • Plymouth
  • 1986 K100RS

Offline Huwj29

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Re: Milky gearbox oil
« Reply #5 on: August 28, 2019, 03:45:07 AM »
See attachment
  • Plymouth
  • 1986 K100RS

Offline Huwj29

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Re: Milky gearbox oil
« Reply #6 on: August 28, 2019, 03:46:10 AM »
Is this oil ok for the gearbox
  • Plymouth
  • 1986 K100RS

Offline Huwj29

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Re: Milky gearbox oil
« Reply #7 on: August 28, 2019, 03:47:36 AM »
Should I be concerned about a drip of engine oil coming from the hole in the bell housing?
  • Plymouth
  • 1986 K100RS

Offline Laitch

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Re: Milky gearbox oil
« Reply #8 on: August 28, 2019, 05:43:24 AM »
Is this oil ok for the gearbox
You're acting like you refuse to believe manufacturers' published specifications and the labels on products you might buy. The only other reason for your question would be that you have difficulty reading. It would help those responding to your question here if you would tell us which is your problem.

  • Along the Ridley in Vermont.
  • 1995 K75 72,000 miles
I wept because I had no radials until I met a man who had no splines.
http://www.motobrick.com/index.php/topic,296.msg53303.html#msg53303

Offline E30_Crazy

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Re: Milky gearbox oil
« Reply #9 on: August 28, 2019, 06:23:32 AM »
Oil from that weep hole is a telltale of the rear main seal and/or gearbox input shaft seal. In my experience it only gets worse, and will saturate the clutch, causing slip and excessive wear.
  • Newport News, Virginia
  • '85 K100, '93 K1100RS

Offline Laitch

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Re: Milky gearbox oil
« Reply #10 on: August 28, 2019, 06:46:19 AM »
Oil from that weep hole is a telltale of the rear main seal and/or gearbox input shaft seal. In my experience it only gets worse, and will saturate the clutch, causing slip and excessive wear.
If it's gear oil, it will have a strong odor unlike engine oil.

My experience has shown that an engine output shaft o-ring can be also be the source of engine oil leaking from this hole sometimes, and that might not affect clutch performance for tens of thousands of miles, if ever. As E30 implies, any leak from that weep hole should be investigated; how soon it is investigated depends upon personal tolerance of uncertainty, and whether enough necessary lubricant has been lost to leave you stranded along the roadside destined to search for replacement parts.
  • Along the Ridley in Vermont.
  • 1995 K75 72,000 miles
I wept because I had no radials until I met a man who had no splines.
http://www.motobrick.com/index.php/topic,296.msg53303.html#msg53303

Offline Huwj29

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Re: Milky gearbox oil
« Reply #11 on: August 28, 2019, 08:19:16 AM »
the drip is definitely engine oil, so going to drop the gearbox out as i have always talked about painting the frame so may as well do it.
will a split clutch boot allow water into the gear box to make the oil milky?
  • Plymouth
  • 1986 K100RS

Offline Laitch

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Re: Milky gearbox oil
« Reply #12 on: August 28, 2019, 08:53:55 AM »
. . .will a split clutch boot allow water into the gear box to make the oil milky?
Unlikely. Idleness and changing temperature or a blown head gasket will cause that from either water or coolant infiltrating the oil.

In your opening post you claimed the milky fluid was transmission oil. Is it now your opinion it is engine oil, or is this a separate condition?

It's unwise to prettify your frame and accessorize your moto until you're certain you have a working engine and transmission to run it, unless it's just going to be for posing.
  • Along the Ridley in Vermont.
  • 1995 K75 72,000 miles
I wept because I had no radials until I met a man who had no splines.
http://www.motobrick.com/index.php/topic,296.msg53303.html#msg53303

Offline Scott

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Re: Milky gearbox oil
« Reply #13 on: August 28, 2019, 08:55:32 AM »
I would think the easiest place for water to enter the gearbox would be through the fill hole, bad sealing washer, loose, etc while sitting in the rain maybe. 
  • SoCal
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Offline E30_Crazy

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Re: Milky gearbox oil
« Reply #14 on: August 28, 2019, 09:06:39 AM »
If it's gear oil, it will have a strong odor unlike engine oil.

My experience has shown that an engine output shaft o-ring can be also be the source of engine oil leaking from this hole sometimes, and that might not affect clutch performance for tens of thousands of miles, if ever. As E30 implies, any leak from that weep hole should be investigated; how soon it is investigated depends upon personal intolerance of uncertainty, and whether enough necessary lubricant has been lost to leave you stranded along the roadside destined to search for replacement parts.

Whoops, got mixed up on the shaft seals, especially seeing as it's not gear oil at the weep hole.
  • Newport News, Virginia
  • '85 K100, '93 K1100RS

Offline E30_Crazy

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Re: Milky gearbox oil
« Reply #15 on: August 28, 2019, 09:08:04 AM »
So is it milky gear oil, or engine mayo?
  • Newport News, Virginia
  • '85 K100, '93 K1100RS

Offline Huwj29

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Re: Milky gearbox oil
« Reply #16 on: August 28, 2019, 12:42:36 PM »
sorry my confusion, 2 different issues.

the milky oil is from the gearbox! and on investigating that I saw a drop of engine oil come from the bell housing, so obvoiusly a seal gone. so gearbox off for that one.

Whats the recommended gearbox oil? I see loads of different grade recommendations on the net. I have 10 liters of EP90 and was wondering if that would do the job to help flush the gearbox
  • Plymouth
  • 1986 K100RS

Offline Laitch

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Re: Milky gearbox oil
« Reply #17 on: August 28, 2019, 03:16:47 PM »
I have 10 liters of EP90 and was wondering if that would do the job to help flush the gearbox
Fer gawdsake, how many times do you need to be told? Let us know.
  • Along the Ridley in Vermont.
  • 1995 K75 72,000 miles
I wept because I had no radials until I met a man who had no splines.
http://www.motobrick.com/index.php/topic,296.msg53303.html#msg53303

Offline stokester

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Re: Milky gearbox oil
« Reply #18 on: August 28, 2019, 03:20:29 PM »
If it's gear oil, it will have a strong odor unlike engine oil.

My experience has shown that an engine output shaft o-ring can be also be the source of engine oil leaking from this hole sometimes, and that might not affect clutch performance for tens of thousands of miles, if ever. As E30 implies, any leak from that weep hole should be investigated; how soon it is investigated depends upon personal tolerance of uncertainty, and whether enough necessary lubricant has been lost to leave you stranded along the roadside destined to search for replacement parts.
I had a similar leak from my K75 but ran it for a couple of years before replacing the seals.  There was no negative effect on clutch performance so I let it go.

When I had the transmission out; the engine rear main seal, output shaft o-ring and clutch disc was all replaced.  Now no leaks. 

Don't know your mileage but if you are going to replace a seal/o-ring then it may be time to replace all those components as well as the clutch as long as you're in there.
  • Yorktown, Virginia
  • '94 K75S Dakar Yellow - '93 K75S Seiden Blau - '91 R100RT Dark Blue- '78 R100S Smoke Red

Offline Laitch

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Re: Milky gearbox oil
« Reply #19 on: August 28, 2019, 04:54:08 PM »
I would think . . .
Sometimes what we think and what is do not coincide. There is no doubt though, that water can enter through a hole if it isn't plugged. :-)
  • Along the Ridley in Vermont.
  • 1995 K75 72,000 miles
I wept because I had no radials until I met a man who had no splines.
http://www.motobrick.com/index.php/topic,296.msg53303.html#msg53303

Offline Huwj29

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Re: Milky gearbox oil
« Reply #20 on: August 28, 2019, 05:08:34 PM »
Fer gawdsake, how many times do you need to be told? Let us know.

Not very constructive
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  • 1986 K100RS

Offline Laitch

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Re: Milky gearbox oil
« Reply #21 on: August 28, 2019, 05:29:34 PM »
Not very constructive
You've had your questions answered already.
  • Along the Ridley in Vermont.
  • 1995 K75 72,000 miles
I wept because I had no radials until I met a man who had no splines.
http://www.motobrick.com/index.php/topic,296.msg53303.html#msg53303

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