Author Topic: transmission fluid poll  (Read 24560 times)

Offline DavidATL

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transmission fluid poll
« on: January 15, 2017, 09:43:19 PM »

I'd like to improve the 1-2 shift on my K75.

This is my second K-bike and neither had a great 1-2 shift. I don't know all the history of my current bike but I believe it has BMW Super Syn that is at least 10 years old. No idea regarding mileage but the bike only has 19k. The transmission drain plug is about as dirty as the rest of the underside so it was not changed recently.

Given the unknown but multi-year age, any change is warranted and will probably improve things. Even so, I thought I'd consult the Motobrick hive via a most unscientific method: the voluntary anecdote-based poll!!!!! So...

What do you use?

These seem the most popular:
- BMW Super Synthetic gear oil SAE 75W140
- Mobil 1 75w140
- Mobil 1 75w140 + Liqui Moly 2019 MoS2 Anti-Friction Gear Lubricant
- Redline Heavy ShockProof

or some other witch's brew of dead dino squeezings and slick-as-snot nasa goop?
  • Atlanta
  • K75RT '92 w/ 28k miles (former bikes: '82 FT500, 80's GL500 Silverwing, 550 Nighthawk and FINALLY an '88 K75S) https://georgiaroads.wordpress.com including my #GA4corners route

Offline Chaos

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Re: transmission fluid poll
« Reply #1 on: January 15, 2017, 10:33:58 PM »
Valvoline synthetic 75-90 helped mine, but that 1 - 2 shift is never going to be buttery smooth.  Best bet is to spend some time on a Ural, after crunching that box of rocks the K will seem like an automatic.
  • sw ohio
1987 K75S    VIN 0231
Original owner, Original litter
200,000 miles (plus or minus) and 5 paint jobs
sold 6/23
2023 Ural 2WD sidecar (BMW's bastard step child)

Offline The Mighty Gryphon

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Re: transmission fluid poll
« Reply #2 on: January 15, 2017, 10:37:04 PM »
I use synthetic gear lube(no specific brand, but mostly Mobil 1) to which I add about 2-3 heaping tablespoons of 1.5 micron molybdenum disulfide powder.  It takes about a hundred miles to completely treat the internals, but I have noticed a noticeable improvement in the smoothness of shifting, especially down from 3rd to 2nd and 2nd to 1st.

I also lube the transmission input shaft splines with Honda Moly 60 to help the clutch disengage smoothly.  This is another maintenance item that helps with downshifting.
  • In my garage in Marilla, NY
  • '91K100RS White/Blue
Current:
'91 K100RS16V "Moby Brick Too"

Past:
'94 K75RT "Ilsa, She Wolf of the SS"
'92 K100RS16V "Moby Brick" (RIP, deceased in a vehicular assault)
'94 K75S Special Edition Dakar Yellow "Cheetos"
'89 K100RS Special Edition "Special Ed"

Offline DavidATL

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Re: transmission fluid poll
« Reply #3 on: January 16, 2017, 05:41:45 AM »

...
 Best bet is to spend some time on a Ural, after crunching that box of rocks the K will seem like an automatic.


now that is funny, right there. :-)



...
also lube the transmission input shaft splines with Honda Moly 60 to help the clutch disengage smoothly.  This is another maintenance item that helps with downshifting.



I did this right after I purchased the bike last summer and it did make some improvement. It was pretty dry but fortunately didn't have significant wear on the splines. I have 2 or so applications left of Guard Dog moly (aka unobtainium).


I know the K transmission will never shift like my prior Hondas. But the rest of the bike MORE than makes up for it! :-)



  • Atlanta
  • K75RT '92 w/ 28k miles (former bikes: '82 FT500, 80's GL500 Silverwing, 550 Nighthawk and FINALLY an '88 K75S) https://georgiaroads.wordpress.com including my #GA4corners route

Offline The Mighty Gryphon

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Re: transmission fluid poll
« Reply #4 on: January 16, 2017, 09:44:02 AM »
Put some of this stuff in your transmission and it will help make things more like a Honda.

http://www.ebay.com/itm/391442186584?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT
  • In my garage in Marilla, NY
  • '91K100RS White/Blue
Current:
'91 K100RS16V "Moby Brick Too"

Past:
'94 K75RT "Ilsa, She Wolf of the SS"
'92 K100RS16V "Moby Brick" (RIP, deceased in a vehicular assault)
'94 K75S Special Edition Dakar Yellow "Cheetos"
'89 K100RS Special Edition "Special Ed"

Offline Laitch

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Re: transmission fluid poll
« Reply #5 on: January 16, 2017, 09:46:44 AM »
Have you adjusted your clutch cable and lever free play?
  • Along the Ridley in Vermont.
  • 1995 K75 89,000 miles

Offline K1300S

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Re: transmission fluid poll
« Reply #6 on: January 16, 2017, 10:43:31 AM »
redline 75w90ns
Project Thread "K75s Midlife Refresh"
http://www.motobrick.com/index.php/topic,7810.0.html

Offline wmax351

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Re: transmission fluid poll
« Reply #7 on: February 12, 2017, 04:26:08 PM »
The Redline shockproof stuff is ideal for this application.
  • Albuquerque, NM
  • 91 BMW K75 Standard, 98 Moto Guzzi California EV
Bikes:
Current:1991 BMW K75 Standard, 1998 Moto Guzzi California EV11
Past: '83 BMW R65LS, '75 Honda CB550F, '69 Honda CB175, 1999 Royal Enfield Bullet 500, 1973 Triumph Tiger TR7V, 1971 BMW R75/5 in Toaster outfit, 1979 Harley Davidson XLS-1000 Sportster Roadster

Offline billday

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Re: transmission fluid poll
« Reply #8 on: February 12, 2017, 05:37:05 PM »
+1 on making sure your mechanism is adjusted correctly.

And spline maintenance is essential.
  • New York State, USA 10977
  • 1985 K100

Offline DavidATL

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Re: transmission fluid poll
« Reply #9 on: February 12, 2017, 07:24:06 PM »
Release lever free play is a shade over 3mm measured when cold. Might be 3.5.
  • Atlanta
  • K75RT '92 w/ 28k miles (former bikes: '82 FT500, 80's GL500 Silverwing, 550 Nighthawk and FINALLY an '88 K75S) https://georgiaroads.wordpress.com including my #GA4corners route

Offline jay1622

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Re: transmission fluid poll
« Reply #10 on: April 20, 2017, 11:38:24 AM »
The Redline shockproof stuff is ideal for this application.


Wanted to ask if you're using this stuff, and if so, which one? The only shockproof line that matches up is...


https://www.redlineoil.com/product.aspx?pid=44&pcid=4


Is this the one?
  • Charlotte
  • Previous: 1986 K75S, 1977 R75/7, 1999 R1200C, 2003 R1150GS, 2001 F650GS, 2005 R1200RT... Current: 2005 R1200RT and my Brick, a 1988 K75S

Offline K1300S

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Re: transmission fluid poll
« Reply #11 on: April 20, 2017, 11:54:18 AM »

Wanted to ask if you're using this stuff, and if so, which one? The only shockproof line that matches up is...


https://www.redlineoil.com/product.aspx?pid=44&pcid=4


Is this the one?

try here
https://www.redlineoil.com/Products.aspx?pcid=8

there are three levels.  lightweight version is roughly the needed one.

i wouldn't use it in a tranny though. wouldn't hurt, but the 75w90NS works fine.  i only use shockproof in my race car differentials.  we call it "blue goo"..for a reason.  whatever you put it in will forever be coated in the medium blue color the oil is.
Project Thread "K75s Midlife Refresh"
http://www.motobrick.com/index.php/topic,7810.0.html

Offline RobP

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Re: transmission fluid poll
« Reply #12 on: April 23, 2017, 04:08:43 PM »
Hey Gryph - how much of that aforementioned Moly powder do you add to the transmission?   
  • Driftwood, TX
  • 1985 K100RS

Offline Laitch

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Re: transmission fluid poll
« Reply #13 on: April 23, 2017, 04:14:35 PM »
Hey Gryph - how much of that aforementioned Moly powder do you add to the transmission?
See Reply #2, RobP.
  • Along the Ridley in Vermont.
  • 1995 K75 89,000 miles

Offline wmax351

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Re: transmission fluid poll
« Reply #14 on: April 23, 2017, 04:23:38 PM »

Wanted to ask if you're using this stuff, and if so, which one? The only shockproof line that matches up is...


https://www.redlineoil.com/product.aspx?pid=44&pcid=4


Is this the one?


I'm using the heavy. It's fluid friction/viscosity is equivalent to the normal 75w90 GL5 that is recommended.


Ostensibly you could use the light stuff for a little less fluid drag. It supposedly still has adequate film thickness, but is a bit thinner viscosity wise. .



  • Albuquerque, NM
  • 91 BMW K75 Standard, 98 Moto Guzzi California EV
Bikes:
Current:1991 BMW K75 Standard, 1998 Moto Guzzi California EV11
Past: '83 BMW R65LS, '75 Honda CB550F, '69 Honda CB175, 1999 Royal Enfield Bullet 500, 1973 Triumph Tiger TR7V, 1971 BMW R75/5 in Toaster outfit, 1979 Harley Davidson XLS-1000 Sportster Roadster

Offline jay1622

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Re: transmission fluid poll
« Reply #15 on: April 23, 2017, 09:34:45 PM »
So, Castrol stopped making the SAF-XO, and changed things over to Syntrax. BMW-Motortad has its own SAF-XO now, which I got for $19 a quart. I put that in tonight to both final drive and gearbox. I've got a ton of residual liquid-moly in there, so I'm going leave it at that for now and see how she responds.


Random thought... That BMW SAF-XO is made here in the US. I wonder who is making it for them.
  • Charlotte
  • Previous: 1986 K75S, 1977 R75/7, 1999 R1200C, 2003 R1150GS, 2001 F650GS, 2005 R1200RT... Current: 2005 R1200RT and my Brick, a 1988 K75S

Offline F14CRAZY

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Re: transmission fluid poll
« Reply #16 on: April 23, 2017, 09:47:44 PM »
I run Supertech (Walmart) 75w90 synthetic blend mostly because that's what I use in my Subaru transmission...in that application this oil provides the best shifting. Dudes over on the Forester forum have looked over the technical data on this oil and it's good stuff protection wise. And it's cheap. I change it every other engine oil change.

If it helps, the owner of BMW of Grand Rapids, when I had them replace the seal in my final drive, said that changing the oil in the final drive often is more important than the brand or "quality" of the oil and suggested doing it at every oil change.
  • Grand Rapids, MI
  • '87 K75C
'87 K75C w/ Pichler V1 fairing. LED's, CATZ driving lights, Audiovox cruise, LT top case, tons of other mods by Drake...


Offline BrickMW

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Re: transmission fluid poll
« Reply #17 on: April 25, 2017, 11:16:52 AM »
I add about 2-3 heaping tablespoons of 1.5 micron molybdenum disulfide powder.


Hey gryph, +1 on the link, mine will be here Fri :2thumbup:


Is that 2-3 TB's per ?? (Gearbox/Final Drive/Liter of Lube?) Mix before fill? or spoon in powder to gearbox before/after lube?
 :beer:
  • Huntsville, AL
  • 1986 K75c
Luft & Jager... My two favorite Meister's :bmwsmile

Offline The Mighty Gryphon

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Re: transmission fluid poll
« Reply #18 on: April 25, 2017, 11:53:35 AM »
I added mine about two months after I changed the oil.  Stuck a funnel in the transmission filler and put in two rounded tablespoons of powder.  The powder is kind of light and fluffy, so I figure it all just floated on the oil until I rode the bike a while.  After about 20-30 miles the shifting started to feel easier, especially the down shifting. 

I don't know if the powder settles when the bike is parked, but I have noticed that if I don't use the bike for a week or more, it takes a couple minutes for the transmission to feel real smooth again.

For the final drive I use one rounded tablespoon.   Basically, I am trying to use about half a bottle of powder for each bike.

I have heard of people using an old blender to mix the moly powder into the oil before adding it.  I will probably mix it in with the oil before I put it in the next time which will be this fall when I do my winter maintenance jobs.  I suppose you can just put it in the oil bottle and give it a good shake for a couple minutes. 

Just remember to avoid the temptation to put it in the engine.  The stuff is so slippery it will keep your sprag clutch from working.  I found that out the hard way when I used a bunch of moly assembly paste when I did some engine work and a week later the sprag wouldn't engage.  Had to flush the engine to get it out and make the sprag work again.
  • In my garage in Marilla, NY
  • '91K100RS White/Blue
Current:
'91 K100RS16V "Moby Brick Too"

Past:
'94 K75RT "Ilsa, She Wolf of the SS"
'92 K100RS16V "Moby Brick" (RIP, deceased in a vehicular assault)
'94 K75S Special Edition Dakar Yellow "Cheetos"
'89 K100RS Special Edition "Special Ed"

Offline DavidATL

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Re: transmission fluid poll
« Reply #19 on: September 04, 2017, 04:51:18 PM »
I know this is bumping a rather old topic. sorry ...

It's been about 300 miles since I put the first tablespoon of moly powder in the transmission. The first 200 were marginally better. Today's 100 mile ride was MUCH better. I plan to follow up with a 2nd tablespoon at the next service. Thanks for the great suggestion!
  • Atlanta
  • K75RT '92 w/ 28k miles (former bikes: '82 FT500, 80's GL500 Silverwing, 550 Nighthawk and FINALLY an '88 K75S) https://georgiaroads.wordpress.com including my #GA4corners route

Offline stokester

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Re: transmission fluid poll
« Reply #20 on: September 04, 2017, 09:22:43 PM »
I know this is bumping a rather old topic. sorry ...

It's been about 300 miles since I put the first tablespoon of moly powder in the transmission. The first 200 were marginally better. Today's 100 mile ride was MUCH better. I plan to follow up with a 2nd tablespoon at the next service. Thanks for the great suggestion!
I'm considering trying it although I use Mobil 1.  Thanks for the update.
  • Yorktown Virginia
  • '94 K75S Dakar Yellow - '93 K75S Seiden Blau - '91 R100RT Bermuda Blue- '78 R100S Smoke Red

Offline Laitch

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Re: transmission fluid poll
« Reply #21 on: September 04, 2017, 09:47:44 PM »
NAPA 80W90
  • Along the Ridley in Vermont.
  • 1995 K75 89,000 miles

Offline BlitzenGruv

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  • My first BMW. Been riding old British forever..
Re: transmission fluid poll
« Reply #22 on: September 05, 2017, 12:55:55 AM »
Don't know what's in mine. It's blue, so I know it's synth.
I use dino 80/90 2/3 with 1/3 STP in the Brit boxes and they shift slick.
  • Crossville, TN
  • '92 K100rs, 16v, '71 BSA Lightning, '72 Triumph Bonneville, '72 Triumph Trident
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Offline bizzaro

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Re: transmission fluid poll
« Reply #23 on: September 17, 2017, 08:03:35 PM »
Having second thoughts on the molly though.  It may help some, but I think most of it ends up as sludge in the bottom of the tranny and final drive.  My drain plugs were covered with the junk from my last oil change. :dunno2:   This time around I shook the molly up in the bottle by adding a little at a time, shaking, doing it again, and again etc.  It worked..... short of.  Kind of lumpy at times, not bad though, and a lot of it settles to the bottom.  If I use molly again, I will add it dry to the top of the fresh oil via the filler hole I think.  Last time I changed the transmission and final drive fluid, I tried to stir the molly into the oil in my measuring cup. :hehehe :hehehe That's how that went.
  • Vermont
  • Current:1994 BMW K1100LT Previous: 1982 Yamaha virago 920,1973 Honda CB550,1976 Yamaha 650 Special
See Ya in the Twisties,
 Bizz

Offline MIbrick

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Re: transmission fluid poll
« Reply #24 on: September 17, 2017, 08:21:27 PM »
If I do it again I will add it dry to the top of the fresh oil via the filler hole I think.


This is how I did it for both the transmission and the FD. It didn't occur to me to pre-mix and pour. Next time, I won't use a plastic funnel to dump the powder in, though. Probably use a paper funnel that I can just dispose afterwards. Probably didn't help that I used the same funnel that I'd used to fill said transmission and FD, so it was already wet with lube.  What an effing mess.
  • Michigan
  • 1986 K100RS (ohne Tragkorb)

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