Author Topic: Changing rear diff gear oil - Very black (normal?)  (Read 2860 times)

Offline Wayne'o

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Changing rear diff gear oil - Very black (normal?)
« on: July 10, 2018, 04:31:21 PM »
Hello all.

Just starting to check over my new ST1100 and decided to drain engine and rear gear/diff oil after going
for a 30 mins ride this morning.

Two things I noticed, 1. engine oil at the end of the ride was cool enough to put your fingers in the drain bowl. I would have
thought a 30 min ride would have warmed it up more. Ambient temp was 14.6C at the time. 2. Rear diff oil was very very dark
and I would say darker than the engine oil.

I will continue to check over this bike because I am now feeling that it may have been overdue for a service. I would have done so
anyway but will now look a little closer and deeper.

From your experience, is what I am finding normal?  I was surprised how dark the rear diff oil was. It looked and felt  like old
engine oil. I have drained it and already replaced it, so hopefully all good.

Any comments much appreciated. No problem but just a little surprised at both of these findings.
Love the bike though, you can feel the precision everywhere that is built into it.

cheers and happy travels.

Wayne

 :dred11
Honda - CB360, CL250, CH250,CB900, XL750, ST1300, CX500, ST1100, NT700.
Yamaha - XT600, FJ1100, T-Max, XJ1200, XJR1300, XV1100, XV1100 Virago, MT-01, TDM900.
Kawasaki - KLR600
BMW - R65, K75S, R100, R1100
Triumph - T509
Suzuki - RG250, CL50 Boulevarde, Vstrom 1000, GSX1400, Burgman 650, GS1100G
 

Online Brock

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Re: Changing rear diff gear oil - Very black (normal?)
« Reply #1 on: July 10, 2018, 06:08:39 PM »
My diff oil was never black, still translucent. You only use about 30mil of oil each time ( hypoy 90), so a litre bottle lasts a long time.

Put in fresh oil, ride for a week and change again, just to clean it out.

The 1100 isnt a hot running bike (unless its mid summer in heavy traffic), so a quick ride will get the oil hot enough for the change, but not hot enough to burn your fingers.
Brock
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Offline alans1100

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Re: Changing rear diff gear oil - Very black (normal?)
« Reply #2 on: July 10, 2018, 07:17:46 PM »
Please note we do not have a diff on our 1100s even though diff oil is used for lubrication.

I just let the bike idle on centre stand for about 10 minutes and while that's happening I get everything I need for the change. Oil is warmish though I try and avoid contact just in case it's hotter than expected. Not fussed with the colour after 12,000 km as the old stuff is getting tossed.

Final drive unit usually gets done every 30,000km though lately I try and do it every 2nd or 3rd oil/filter change 24 or 36,000km again colour out I haven't really taken much notice of.

When I replaced the final drive with a used unit what little oil was left inside after meeting US export needs was fairly dark and the splines were perfect and that was that mattered.




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Offline Biggles

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Re: Changing rear diff gear oil - Very black (normal?)
« Reply #3 on: July 10, 2018, 07:50:24 PM »
Two things I noticed, 1. engine oil at the end of the ride was cool enough to put your fingers in the drain bowl. I would have
thought a 30 min ride would have warmed it up more. Ambient temp was 14.6C at the time. 2. Rear diff oil was very very dark
and I would say darker than the engine oil.

These cooler days the engine doesn't get hot enough to burn your fingers with the oil, as Brock says.  It's at its hottest as it flows out, but cools quickly in the pan due to the stream and large surface area.

The final drive oil should be fairly clear and certainly not as black as used engine oil.  It might have been neglected for a very long time.  The colour in the engine oil is from the combustion process, so I suspect the drive oil is black from age.  I'd suggest you do a change with the next engine oil change and expect it to be cleaner.  If it were mine, I'd take the bottom plug out and run a bit of kerosene or diesel through it to flush out any sludge that might be sitting in the bottom, followed by a squirt of 80 Hypo to flush the kero.
For the modern man who lives in the city, riding a bike might be one of the only ways to escape the humdrum monotony. To take off and ride. To be both at one with nature and one with the bike. To feel masculine. Adam Piggott

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Offline Wayne'o

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Re: Changing rear diff gear oil - Very black (normal?)
« Reply #4 on: July 11, 2018, 10:18:06 AM »

Thanks Biggles.

I did expect to find the engine oil black due to carbon and it certainly wasn't out of the ordinary,
but it did surprise me that it was only a little more than luke warm. With some of the many bikes
that I have owned in the past, I quickly (and painfully) learned that the oil can also very hot after
a fairly short ride. The GSX1400 that I just sold had an oil capacity of 5+ litres and this engine was
oil/air cooled and was quickly too hot to put your fingers in the oil. I suspected that with the ST1100,
having a capacity of 3.8L that it would perhaps at least be just as hot, but it wasn't.

I thought also from past bikes with shaft drive that the oil would be fairly clear so that was also a
surprise to find it black as charcoal. I did flush it out before adding the new stuff and will change it
at the next oil change time.

I was told that all maintenance on this bike had been done by a dealer but I am now thinking that perhaps
that dealer had not held up his end of the deal but more than likely charged for doing it.  :spank

I will finish the oil change today and over the next week (rather busy at the moment) check the air filter and
plugs.

But in the meantime, I am very impressed with the way it goes and with the TLC that I will give it, hopefully
even better.

Thanks for responding.

Wayne

 :dred11
Honda - CB360, CL250, CH250,CB900, XL750, ST1300, CX500, ST1100, NT700.
Yamaha - XT600, FJ1100, T-Max, XJ1200, XJR1300, XV1100, XV1100 Virago, MT-01, TDM900.
Kawasaki - KLR600
BMW - R65, K75S, R100, R1100
Triumph - T509
Suzuki - RG250, CL50 Boulevarde, Vstrom 1000, GSX1400, Burgman 650, GS1100G
 

Offline hobs

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Re: Changing rear diff gear oil - Very black (normal?)
« Reply #5 on: July 11, 2018, 09:23:59 PM »
That's the main reason I take the back wheel off myself and bring it to the bike dealers for a tyre change. The previous rear tyre changes done before I owned the bike, it was obvious that the drive spline has never been lubricated for a very, very long time. Haven't found dealer, both bike or car that doesn't cut corners and skim dollars for jobs not done.


Cheers, Hobs
 

Offline Biggles

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Re: Changing rear diff gear oil - Very black (normal?)
« Reply #6 on: July 11, 2018, 09:45:56 PM »
That's the main reason I take the back wheel off myself and bring it to the bike dealers for a tyre change. The previous rear tyre changes done before I owned the bike, it was obvious that the drive spline has never been lubricated for a very, very long time. Haven't found dealer, both bike or car that doesn't cut corners and skim dollars for jobs not done.

Possible confusion here- the rear drive oil is 80 grade Hypoid oil that is changed via drain and filler caps on the right side of the rear drive.  The spline lubrication with Moly grease is applied to the splines when the rear wheel is removed, as suggested in your description.
For the modern man who lives in the city, riding a bike might be one of the only ways to escape the humdrum monotony. To take off and ride. To be both at one with nature and one with the bike. To feel masculine. Adam Piggott

OzSTOC #16  STOC #6135  FarR #509  IBA #54927
 

Offline alans1100

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Re: Changing rear diff gear oil - Very black (normal?)
« Reply #7 on: July 11, 2018, 09:55:23 PM »
That's the main reason I take the back wheel off myself and bring it to the bike dealers for a tyre change. The previous rear tyre changes done before I owned the bike, it was obvious that the drive spline has never been lubricated for a very, very long time. Haven't found dealer, both bike or car that doesn't cut corners and skim dollars for jobs not done.

Possible confusion here- the rear drive oil is 80 grade Hypoid oil that is changed via drain and filler caps on the right side of the rear drive.  The spline lubrication with Moly grease is applied to the splines when the rear wheel is removed, as suggested in your description.
I think he maybe referring to part of my comment

When I replaced the final drive with a used unit what little oil was left inside after meeting US export needs was fairly dark and the splines were perfect and that was that mattered.
1999 :bl11  2004 :13Candy

FarRider #921- BR15, BR17, CR1