Author Topic: Shot splines?  (Read 19530 times)

Offline szabgab

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Shot splines?
« on: October 05, 2018, 04:51:28 PM »
Dear all,

Finally I managed to delve into my 130.000 km '85 K75S' final drive and drive shaft business. The situation seems to be rather bad, or is it? To my untrained eyes it looks like, the splines are pretty much shot, especially on the drive shaft side, please see the shed load of images, I have attached. Is this catastrophe waiting to happen or the doom is not knocking on the door as yet? Also upon dis-assembly a large-ish quantity of rust coloured light oily fluid came out of the shaft housing, you can see that on the first pictures... What the hell is that? Is it gear oil mixed with water and rust from the shaft? There was this fluid and a lot of brown coloured mud like crap, that was hard to clean off, I did at the end, and lubed the splines very thoroughly with LM47 Liqui Moly (we don't have any Honda Moly 60 around here, and this is the stuff, Haynes calls for), but what is this? I would guess it is possibly water ingress through some torn rubber, but where is the oil coming from? Leaking seal on the gear shaft? I could not go in any deeper into the bike this time around, but what should I check next time? Also if there is water present, especially in largish quantities, would that wash of the grease quickly?

Thank you!

Gabriel
  • Budapest, Hungary
  • K75S 1985 model

Offline natalena

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Re: Shot splines?
« Reply #1 on: October 05, 2018, 05:10:47 PM »
Yikes. Looks like Tiger Shark teeth. If it were mine, I'd replace the parts as it looks close enough to "it'll fail soon enough" and will probably happen at the worst possible time. Then again, I defer to the experts who may demonstrate much more on-road courage and faith in BM metallurgy than me. :)
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Offline Martin

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Re: Shot splines?
« Reply #2 on: October 05, 2018, 05:21:54 PM »
Try Honda car dealer for the grease or a  Subaru dealer. Alternatively BMW have come up with a new spline grease Castrol Molub- Alloy paste TA BMW part No 18 21 9 062 599.

Regards Martin.
  • North Lakes Queensland Australia
  • 1992 K75s Hybrid, Lefaux, Vespa V twin.

Offline Laitch

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Re: Shot splines?
« Reply #3 on: October 05, 2018, 06:01:25 PM »
To my untrained eyes it looks like, the splines are pretty much shot, especially on the drive shaft side, please see the shed load of images, I have attached. Is this catastrophe waiting to happen . . . ? Also upon dis-assembly a large-ish quantity of rust coloured light oily fluid came out of the shaft housing, you can see that on the first pictures... What the hell is that? Is it gear oil mixed with water and rust from the shaft?
It is inconvenience waiting to happen. When the remaining tips of those driveshaft output splines break off, there will be sustained screeching while the transmission is in gear and forward motion under power will stop; you'll be coasting. You do not have hundreds of miles remaining on those driveshaft splines. The final drive splines appear to be in somewhat better condition and that is not unusual.

If the oil in the brown, oily, mud mix smells like sulfur, it could be leaking from around the transmission output shaft as seen in the attached image. The forward connection of the driveshaft to the transmission output shaft is covered by a boot that might be ripped or missing altogether. The boot keeps water and grit from affecting the u-joint connection. The brown tint is likely rust from the driveshaft cause by water in the oily, mud mix. The mud might actually be mud. :giggles



I think it would be better for you to keep dismantling all the way to the intermediate engine housing for inspection. Are you using Chris Harris's video as a guide?
  • Along the Ridley in Vermont.
  • 1995 K75 89,000 miles
I wept because I had no radials until I met a man who had no splines.
https://tinyurl.com/RillRider

Offline szabgab

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Re: Shot splines?
« Reply #4 on: October 06, 2018, 02:58:13 AM »
You do not have hundreds of miles remaining on those driveshaft splines. The final drive splines appear to be in somewhat better condition and that is not unusual.

Oh cool, this is what I feared :(

So replacement time is imminent, but is it OK to replace the shaft only, or do they have to go in pair with the final drive? Also if the driveshaft looks this crappy, the clutch splines will be too, is this correct? F... me, there were two things costly to repair on a K75, DS-FS and fuel pump. My fuel pump is an aftermarket piece with the wrong characteristics and meltig rubber surroundings, and the shaft is toasted. Just my luck :(((
  • Budapest, Hungary
  • K75S 1985 model

Offline Laitch

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Re: Shot splines?
« Reply #5 on: October 06, 2018, 03:39:27 PM »
So replacement time is imminent, but is it OK to replace the shaft only, or do they have to go in pair with the final drive? Also if the driveshaft looks this crappy, the clutch splines will be too, is this correct?  Just my luck :(((
You are incorrect about the transmission input/clutch shaft splines. You won't know their condition until you look at them. That shaft could be ok. Having the mating surfaces of the driveshaft and the final drive shaft both in good condition is preferable but they don't need to be in the same condition. Plenty of riders have replaced their driveshafts with used ones in good condition.
  • Along the Ridley in Vermont.
  • 1995 K75 89,000 miles
I wept because I had no radials until I met a man who had no splines.
https://tinyurl.com/RillRider

Offline szabgab

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Re: Shot splines?
« Reply #6 on: October 06, 2018, 04:38:09 PM »
Try Honda car dealer for the grease or a  Subaru dealer. Alternatively BMW have come up with a new spline grease Castrol Molub- Alloy paste TA BMW part No 18 21 9 062 599.

Regards Martin.

I did try Honda and Subaru dealers, for some reason they say, they can not get US stuff in Europe, this sounds like bullsh*t to me, but what can I do? The LM47 is a good lube but it is not a paste, so I might just try to get the Optimol, you mentioned.... after I replaced that sodding driveshaft
  • Budapest, Hungary
  • K75S 1985 model

Offline szabgab

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Re: Shot splines?
« Reply #7 on: October 06, 2018, 05:04:27 PM »
You are incorrect about the transmission input/clutch shaft splines. You won't know their condition until you look at them. That shaft could be ok. Having the mating surfaces of the driveshaft and the final drive shaft both in good condition is preferable but they don't need to be in the same condition. Plenty of riders have replaced their driveshafts with used ones in good condition.

That's somewhat reassuring to hear. The PO, who had the bike for five years has driven only 15.000 km's, but he never lubed either of the shafts. He also never looked at or changed the clutch, but it is not slipping (even though there is oil in the weep hole between the housings) and it is not particularly hard to downshift from 4 to 3 (although the gears are somewhat clunky). Disassembly will have to wait till the winter downtime, I do not have a garage or a helping hand, so I will take the bike to my brother's place in an another town, so we can tackle the issue together. Till then I will watch the Harris videos again a few more times, also the descriptions of the procedure on historical threads here are invaluable (like the trick, how not to rip the clutch boot, or how to align the transmission upon re-assembly).

There is a BMW K specialist in this country, who is also salvaging bikes, he said, he might have a 20T differential (DS+FD) in good nick for about 150-180 USD. He is not willing to separate the parts, as they are forming a pair in his opinion. The price is not that crazy, so I might just go for that, especially, that my rear rotor is about becoming illegal. If he can not help me, I might try the motobins solution (although I'm not crazily excited about the fact, that I need to find a welder, who will not botch up the job). Knowing, what I know, I'm scared to go on trips with this bike, although I might still get away with it for a while... Anyway, I will see on Monday, if this guy has got something for me, if not, well, I will have to thank whoever is to be thanked, that I did not manage to sell my scooter since owning the K :)
  • Budapest, Hungary
  • K75S 1985 model

Offline Laitch

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Re: Shot splines?
« Reply #8 on: October 06, 2018, 05:10:49 PM »
I will have to thank whoever that is to be thanked, that I did not manage to sell my scooter since owning the K :)
You might think your luck is bad but that is good luck. It might be the start of a trend.  :2thumbup:
  • Along the Ridley in Vermont.
  • 1995 K75 89,000 miles
I wept because I had no radials until I met a man who had no splines.
https://tinyurl.com/RillRider

Offline Martin

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Re: Shot splines?
« Reply #9 on: October 06, 2018, 06:10:20 PM »
As far as the lube goes I've used white Optimol paste until the last grease at a 170,000 K's, the splines are still quite serviceable. I am now using the new Optimol silver paste around $30.00 AU. As a precaution I've been chasing a spare stuffed shaft and ordered a new spline from the UK to go with it. While I was waiting for the spline to arrive I found a brand new OEM one on Ebay. I was the only bidder, and got it for $190.00 AU on the starting price. Probably as rare as Unicorn poo, I've never seen one advertised before.
Regards Martin.
  • North Lakes Queensland Australia
  • 1992 K75s Hybrid, Lefaux, Vespa V twin.

Offline szabgab

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Re: Shot splines?
« Reply #10 on: October 07, 2018, 05:15:30 PM »
You might think your luck is bad but that is good luck. It might be the start of a trend.  :2thumbup:

Laitch, thanks for the encouragement, even though I think luck would have been to buy a bike, selling the old one and having the new one in good order, but I have to face the fact, that I have very well thought my splines could be garbage, as the bike is a high mileage one with known neglect in it's history (and God only knows, how many PO's). I'm mostly surprised, there is not more of the home made mechanics' crap (Lada and Skoda parts, insulation tape to holding stuff down), as Hungarians (me included) are usually broke but resourceful :D
  • Budapest, Hungary
  • K75S 1985 model

Offline szabgab

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Re: Shot splines?
« Reply #11 on: October 07, 2018, 05:54:52 PM »
As far as the lube goes I've used white Optimol paste until the last grease at a 170,000 K's, the splines are still quite serviceable. I am now using the new Optimol silver paste around $30.00 AU. As a precaution I've been chasing a spare stuffed shaft and ordered a new spline from the UK to go with it. While I was waiting for the spline to arrive I found a brand new OEM one on Ebay. I was the only bidder, and got it for $190.00 AU on the starting price. Probably as rare as Unicorn poo, I've never seen one advertised before.
Regards Martin.

Martin, that was a business, I'm sure, many of us would have been proud of. BMW is selling a new one for 330 USD or so. If you have used the Optimol for 170k miles and the splines are still OK-ish, that is a good enough reference point for me, to use that from now on. Also they can be bought at my local BMW dealer, which can not be said of the other stuff (especially Guard Dog molly, that is now completely gone even for the Americans)....
  • Budapest, Hungary
  • K75S 1985 model

Offline Martin

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Re: Shot splines?
« Reply #12 on: October 07, 2018, 06:20:03 PM »
The whole spline lube thing is like opening a can of worms, a lot of varied opinions. I think the key to long spline life seems to be frequent lubing, every rear tyre change. Using either a thick high moly content grease or in my case the original Optimol. Both the old Optimol and the new silver Optimol  don't appear to have any Moly content at all which seems to go against current opinion.  When I first got my Brick 20 years ago I bought spline lube of the local BMW dealer part No 07 55 1 223 05 and it is black, a mate who was a BMW tech told me not to use it and to use the white Optimol. So far what I have been using has worked so I'll be sticking with Optimal.  An overseas BMW technician recommended the new silver Optimal saying that BMW is always looking for improved lubricants. It took a bit of wrangling to persuade the local BMW shop to part with it.
Regards Martin.
  • North Lakes Queensland Australia
  • 1992 K75s Hybrid, Lefaux, Vespa V twin.

Offline szabgab

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Re: Shot splines?
« Reply #13 on: October 07, 2018, 07:56:18 PM »
The whole spline lube thing is like opening a can of worms, a lot of varied opinions. I think the key to long spline life seems to be frequent lubing, every rear tyre change.

Yes, indeed, when I was researching the whole grease - paste - whatever issue, there were opposing voices, later I asked the Honda dealership, and they use anything, that has got molly in and is not too expensive :) Chris Harris (if he is the guy, ho swears 24/7 on his videos) puts solely Staburags on the clutch splines, so on, so forth. Anyway, as you said, no leak (which I do have, most likely water ingression through a torn swing arm boot combined with shaft seal leak) and frequent greasing and cleaning helps a ton....

BTW is it possible to replace the drive shaft and output shaft seals without tearing the gearbox to pieces? Also, is there a common and cheap replacement of the shaft seals (probably on both sides of the transmission, as I do not know, what I will find inside, once I get in that deep).

Thanks!
  • Budapest, Hungary
  • K75S 1985 model

Offline szabgab

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Re: Shot splines?
« Reply #14 on: October 08, 2018, 03:19:16 PM »
So, no luck here, the guy does not have any driveshafts, only a final drive, I contacted a salvage yard, thet don't have one either. Ebay stuff is crap and usually 16 teeth, rather than the 20, I have. Motobins is out of stock of the shaft end, anyway, I could not find a welder, who would take this job on. Oh f*ck me sideways, what's next? Does anybody has got one lying around collecting dust?
  • Budapest, Hungary
  • K75S 1985 model

Offline Laitch

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Re: Shot splines?
« Reply #15 on: October 08, 2018, 04:31:03 PM »
Oh f*ck me sideways, what's next?
Suspended from a rafter is the usual next step.

Keep looking. You've got access to a broad network here.
  • Along the Ridley in Vermont.
  • 1995 K75 89,000 miles
I wept because I had no radials until I met a man who had no splines.
https://tinyurl.com/RillRider

Offline szabgab

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Re: Shot splines?
« Reply #16 on: October 09, 2018, 07:54:15 AM »
Suspended from a rafter is the usual next step.

Keep looking. You've got access to a broad network here.

:D Laitch you chuckled me up with that. Sorry for venting earlier, I have so many little nagging issues with this bike, I thought, I might just be lucky this time around, well I was not. The bike had a reasonable price tag but came from an un-knowledgeable PO, who did not do proper maintenance and rather than checking out several K75's, I have bought the first one, I have seen (but liked a lot nevertheless). Cosmetically it is very sound but 130.000 kilometres won't go by unnoticed by a mechanically neglected bike...

BTW, I have noticed, that it does not matter, if the DS end in 20 or 16 tooth, the other side is always 16, is this correct? Does that mean, if I source a whole 16t differential, I can simply swap those parts?
  • Budapest, Hungary
  • K75S 1985 model

Offline Rcgreaves

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Re: Shot splines?
« Reply #17 on: October 10, 2018, 06:20:04 AM »
Nasty splines. Sent PM

I too started my brick infatuation as you thinking I was in for trauma after trauma..and initially that was true.  As you sort this machine you will either fall in love or as you suggest, prefer something newer and low maintenance as care and feeding is very much the way here in the asylum....

For my part I encourage you to get your hands dirty, tackle this and a few of the other known issues and proceed with your courtship.

Visited Hungary briefly in 1980.  Lots of military in the streets, I was intimidated to say the least.  Same with Turkey.   I hope to circumnavigate Europe on a brick.  Cheers.
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Offline szabgab

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Re: Shot splines?
« Reply #18 on: November 08, 2018, 07:37:12 AM »
It is inconvenience waiting to happen. When the remaining tips of those driveshaft output splines break off, there will be sustained screeching while the transmission is in gear and forward motion under power will stop; you'll be coasting. You do not have hundreds of miles remaining on those driveshaft splines. The final drive splines appear to be in somewhat better condition and that is not unusual.

If the oil in the brown, oily, mud mix smells like sulfur, it could be leaking from around the transmission output shaft as seen in the attached image. The forward connection of the driveshaft to the transmission output shaft is covered by a boot that might be ripped or missing altogether. The boot keeps water and grit from affecting the u-joint connection. The brown tint is likely rust from the driveshaft cause by water in the oily, mud mix. The mud might actually be mud. :giggles



I think it would be better for you to keep dismantling all the way to the intermediate engine housing for inspection. Are you using Chris Harris's video as a guide?

OK, so I recieved the goods to repair the shaft... I have taken the swing arm off too to have a look, surely enough the boot is ripped and the transmission seal is leaking. Is it possible to remove it from the outside, or does the transmission needing to be opened up?

Thanks!
  • Budapest, Hungary
  • K75S 1985 model

Offline Laitch

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Re: Shot splines?
« Reply #19 on: November 08, 2018, 10:15:29 AM »
. . . surely enough the boot is ripped and the transmission seal is leaking. Is it possible to remove it from the outside, or does the transmission needing to be opened up?
Your question was answered in the last sentence of Reply #3 of this thread.
  • Along the Ridley in Vermont.
  • 1995 K75 89,000 miles
I wept because I had no radials until I met a man who had no splines.
https://tinyurl.com/RillRider

Offline szabgab

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Re: Shot splines?
« Reply #20 on: November 08, 2018, 10:26:09 AM »
Your question was answered in the last sentence of Reply #3 of this thread.

Sorry Laitch,  if I. missed something there,  I have watched them videos a few times,  but could have missed the info about the trans output shaft seal...  Will watch the long version again...
  • Budapest, Hungary
  • K75S 1985 model

Offline Laitch

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Re: Shot splines?
« Reply #21 on: November 08, 2018, 10:29:37 AM »
If you are not intending to inspect the input shaft spines on the engine side of the transmission, you can install the boot right now. If the input shaft splines are worn, you'll have much more work to do.

With a moto that is showing wear like yours, inspecting the input side of the transmission and the condition of the clutch first is a reasonable and sensible approach.
  • Along the Ridley in Vermont.
  • 1995 K75 89,000 miles
I wept because I had no radials until I met a man who had no splines.
https://tinyurl.com/RillRider

Offline Laitch

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Re: Shot splines?
« Reply #22 on: November 08, 2018, 11:16:00 AM »

The boot isn't the transmission output shaft seal. The boot protects the clutch bearing and clutch pushrod. Is the seal around the splined output shaft leaking also?
  • Along the Ridley in Vermont.
  • 1995 K75 89,000 miles
I wept because I had no radials until I met a man who had no splines.
https://tinyurl.com/RillRider

Offline szabgab

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Re: Shot splines?
« Reply #23 on: November 08, 2018, 12:37:29 PM »
The boot isn't the transmission output shaft seal. Is the seal around the splined output shaft leaking also?

Yes, it is. The boot is cracked, but I have a replacement from Clayton, so that is easy enough. There was oily water inside the swing-arm as you might remember and surely enough there was oil sitting on the bottom of the output shaft seal, so that will be the source of the oil in the mix (also it smells like rotten eggs, so it should be tranny oil). So it is the shaft seal, I am looking at replacing. Now the question is, if I have to split the transmission case in order to get the seal out, or is it possible the dig it out from the outside (basically, is there a seal raised edge? And if there is one, is it inside or outside the case)? The seal is rather expensive from BMW direct, but is there a cheaper alternative? I am aware of the fact, that the main shaft seal should be bought from BMW, as it somehow special in it's form, but this might be different...

On a different note - there is a lot of axial and radial movement of the swing-arm bearings, not just a little, but quite a lot. It does run smooth though and if the swing arm is tightened down properly, it does not have any free play at all. Is that normal or do I need to replace yet another thing?


Thanks!
  • Budapest, Hungary
  • K75S 1985 model

Offline Filmcamera

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Re: Shot splines?
« Reply #24 on: November 08, 2018, 02:53:16 PM »
You do not have to split the transmission to change the seal, you can do it from the outside no problem.
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