Final Drive woes - workable or replacement and if so: which?

FeralSquirrel

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Preamble - I've had my GSA for almost a full year - I like to do all my own work wherever possible (yes, I follow guidance rather than winging it, no worries!) and while coming to grips with some of this particular GS's foibles (winglets could do with replacing but servicable, one grip needs replacing as original is kept together with literal foam tape....) I'm at a bit of an impasse with this one

So in Oct' last year, as it needed doing and I didn't want to do more than ride it home when I bought it, I needed to replace the drive boots - as both looked worse than a WW2 Gas Mask and you'd find more life in an Egyptian Mummy's social calendar if you catch my dfirt. Bought some nice red ones to go with the colour of the bike, whipped the FD off while at it just to get in properly to inspect, clean and appropriately lube up, as they should be. All went well, shaft is looking as good as the U.S based private eye namesake, etc.

Replaced FD oil while at it, because "why not" and peace of mind - also added a magnetic sump plug to both FD and engine oil drain because again, why not.
Now I've not had any issues since - and while (as expected) for a 15 y/o ride she has some corrosion going on so there was a the odd flake here/there, nothing worth worrying about which can't be fixed with some wire rubbing, sandpaper scrubbing and a lick of Hammerite (except the fuel strip which I'll come to sort another time as currently I just run on the odometer to know when to top up again).

Now to the problem: - I found out this Monday on a commute that things were categorically not OK in GS-land, noticed I could hear an odd sort of whirring/buzzing drone noise halfway to work, which as I got faster increased in pitch. I did pull over to do a visual but nothing stuck out and I've gotten used to some noises enough to not panic (i.e bumps and the centre stand clonking). I checked for wheel play, pondereed on it being an alternator belt issue (promptly ordered two, one to replace, one as spare) and plan to swap this out in the coming ~week when they arrive.

Thought nothing more on it until I was nearly home, as while the sound persisted, I then in the last 2 miles noticed "notchiness" to lower speeds and an unimstakably mechanical, physical "clonking" noise when engaging and loosening on/off the clutch and things just felt off (in conjunction with the still-present noise from earlier).

I whipped off the rear wheel, inspected calipers in case it was brake-related (not as far as I could tell, but cleaned down anyway and noted I'll also swap brake pads out in the next week anyway as a precuation and further peace of mind as they'll want doing by the next MOT) - but the big shocker was when I got to wondering about the FD.

I popped the ABS sensor for air, loosened the sump and.....no oil. I hadn't noticed any leakage previously (and this was while leaving her stationary for a week or two at times) and I have a tarmac forecourt - so while I like to think I'd have noticed it, given I like to give her a scrub and good hosing down it's entirely possible I violated the scene of the crime, so to speak.

Regardless, utterly beyond me how/when/where this happened - whether this was just a "slow leak" somehow, I don't know, as the new plug certainly didn't show signs of leaking when I swapped it out, it includes an o-ring to seal.....so maybe I've just got a secret, silent dribbler of a FD?

I also then found a collection of what was evidently metallic residue/collection on the magnetic plug and ABS sensor - not tons, but roughly 1-2mm of it on both, like a thin layer of metallic paint or somesuch - which I looked at like it was Satan's own glitter and frankly worried the sh*t out of me.

So I promptly flushed it out with some new oil, checked the shaft (all fine, seated properly) and cleaned/re-lubed it for good measure, refilled the oil and gave a test ride - much smoother, but there's still this other whining, based-on-speed noise still somewhat present which I've since decided sounds like it's from the front end of the bike - but the whole thing has me worried.

.....To the point I want to source or work out, at least, what I can do for my FD as far as replacement goes.

Having done some research, I know I need to find a matching ratio unit (I would rather, being frank, not balls about with changing ratio anyway) so that's fine - my query, however, is on if anyone knows if I have to stick to the K7 part I currently have (Reads as "K7/1 7712559-02") which goes with that year/model/period of bike (up to 2014 I think I've seen?), or if I can go for a newer one yet - which as a bonus should also have nice luxuries such as the drain, etc.

I need to whip the wheel off yet again to determine my own ratio (haven't yet been able to see as the stamp must be behind the wheel and like a twit I didn't check at the time I had the wheel off etc) - but I would absolutely love to know if A) I should even be riding it given I seem to have "gotten away with it" in terms of all bar the hopefully-just-belt-whinging noise and B) if replacing, what to look out for with a replacement in terms of compatability.

I've seen some good potential ones going for anything from ~£200 or so, some double/triple that (but unless there's a damn good reason why and I'm missing it I'll stick to what I know).

Absolutely peeved given I was planning on nipping on the ferry next week to hit France, but I'd rather say sod it, play it safe and see what the experienced noggins here come back with before I get 10ft outside Calais only to pull a stunt Tony Hawk would be proud of, but both unintentionally and at the cost of my damn bike which I've rather gotten fond of and bonded with blood, sweat, tears and copious amounts of both road tar and grease.
 
FD - whip it off & send it to

Mikeyboy (Overland & Classic) of this parish (give him a call / PM to discuss)

he will work his magic, and normal service will be restored for longer than you will own the bike ( probably)

SH units are a false economy

Wait for the +1's to appear and that may convince you
 
FD - whip it off & send it to

Mikeyboy (Overland & Classic) of this parish (give him a call / PM to discuss)

he will work his magic, and normal service will be restored for longer than you will own the bike ( probably)

SH units are a false economy

Wait for the +1's to appear and that may convince you
Hilariously I've seen mention of Mikeyboy before but honestly thought he was only on the Adv' forums (which apparently aren't taking new registrations at the moment).

I'll give him a ping and see where we go from there, thanks :)
 
+1 for Santa's reply.

I had a strange grinding feeling no noise (GS not the quietist of bikes) and just had the final rear wheel bearing holder replaced by a 2nd hand unit. They had to get the full reg and chassis number to confirm the BUILD date not the registered date so they could match it up. More than happy and bike feeels like new. ps item came from motorworks ....but was not cheap but alot less than a brand new one, good luck sorting out your issue
 
You mentioned your fuel strip had packed up and you were using the trip meter. I had the same 8 years ago but the warnings on the dash pi**ed me off. I found this mod on another forum. It works and I've had it on the bike for over 7 years now.
 

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You mentioned your fuel strip had packed up and you were using the trip meter. I had the same 8 years ago but the warnings on the dash pi**ed me off. I found this mod on another forum. It works and I've had it on the bike for over 7 years now.
Hey dashfixer - thanks for the tip! Does it actually *fix* the fuel strip so it's accurate? Or what exactly?
Is that on the header which goes to the fuel sensor or somewhere else? Would love to know more as the only other two fixes are either the fload mod, or that absolutely terrifying looking one where I've seen people "zap" their strip!
 
The resistor pack mod only gets rid of the light on the dash. You will need to zap pins 2-3 (fuel sensor) and pins 1-4 (heater element) to correct the gas gauge itself. I performed this recently for the first time and it worked like a charm.
 
Mikeyboy rebuilt my final drive ( and most of the rest of my bike ) and it’s been absolutely perfect ever since. :thumb2
You really should give him a bell.
 
FD - whip it off & send it to

Mikeyboy (Overland & Classic) of this parish (give him a call / PM to discuss)

he will work his magic, and normal service will be restored for longer than you will own the bike ( probably)

SH units are a false economy

Wait for the +1's to appear and that may convince you
+1 also

Mikeyboy rebuilt my final drive after i bought the bike and the wheel bearing had a hell of a play. How the previous owner didnt notice is beyond me and worryingly he had just done a tour around the north of Scotland and tried to tell me it was fine. Mental.

Once sorted no issues at all as good as new..

Im not sure if i am allowed to post his mobile but drop me a line and i can pass it on..
 
So just as an update on this, as it's been a while....

I figured before I go doing anything, I'd check a hunch that this *wasn't* my bearings.
Only saying this as when I recently had the bike MOT'd, there was a bit of play before there was engagement of the drive and wheel by rocking it back and foreward.

Got the drive off, checked it again in a vice turning the shaft end and you could feel it getting a little tougher to turn now and again.

I'd already given it a rinse through a few weeks back, but did so again since the trip to the MOT joint and yup, there was (again) more sign of metal in the oil - both the drain plug and ABS sensor looked like little metallic hedgehogs and the oil out of the FD looked like someone had put glitter in it.

To note: no, not chunks and when feeling it between two fingers was basically sludge - no "grittiness". Regardless, not good.

I took this to a guy locally who has better equipment (read: an actual garage and tools as opposed to my lack of one and minimal of the latter) who got the FD open and.....well, see attached.

He was shocked, the guy who's shop we took it to was equally surprised and all around "well, that's banjaxed" - see attached. Looks like the episode of it running without oil was more than enough for it to have totally whacked the internals and it hit a "point of no return". There's absolutely nothing which can be done now apart from replacing the entire thing as there's no swapping out what's been damaged.

So - I'm off now to look for a complete replacement. Local BMW dealership will be back to me to let me know what an OEM part costs, but also looking out on the usual sites to see what's available - ratio is 32/11 so keeping an eye out as trying to determine what else out there has the same teeth number and will work as a compatible replacement, so stay tuned.

If nothing else it at least means I can grab one which is vented now, just a damn shame to be like this!
 
Give mikeyboy a call,

The man is nothing short of a god, when it comes to final drives ( and the rest of the bike too)
 
Yes that’s buggered, be interested to see what BMW charge for a replacement.
Is it a complete rear drive or just crown wheel and pinion?
 
Look at the images...it's all buggered. What a shame. But yes, an entirely new FD is the obvious option

Sent from my SM-S908B using Tapatalk
 
That Actually looks like the end result of when you use GL4 spec oil in the BMW drivetrain (basically case hardening "Erodes" )

A used replacement is a good option and be careful about switching between "types" for example, With the early 1200GS FD you can;t use an 2006 onwards version as the speed sensor and tone ring are a mis match on a pre 2006
 
He said he ran it without oil?
Not knowingly - tl;dr of my OP is I'd done an FD + transmission oil change, felt something off and found the FD had no oil in - 100% absolutely did put it in, torqued the drain bolt to spec and couldn't find sign of a leak but seems it may have.

So yup, utterly banjaxed.

That Actually looks like the end result of when you use GL4 spec oil in the BMW drivetrain (basically case hardening "Erodes" )

A used replacement is a good option and be careful about switching between "types" for example, With the early 1200GS FD you can;t use an 2006 onwards version as the speed sensor and tone ring are a mis match on a pre 2006
I used Putoline SP Gear oil (75W-90) which apparently should've been absolutely fine, as saw others had been using it for their FD/Transmission oil changes and saw no reported issues or concerns with it. No idea if this means I *did* pick the wrong oil still, somehow, as i've since been told I should try using Rock Oil 75W-90 instead?

I have been scouring the place and while there's some options looks like my best bet currently is one in Germany - BMW are giving me a run around to chase from one Motorrad place to another and we all know they'll likely charge a Liver and Kidney for it but I figured it didn't hurt to ask!

Ideally looking for a vented one from 2009 onwards that'll be compatible, which the German one is.

Edit: This is the one I'm currently looking at - unsure if links are allowed or not but if so happy to remove. I believe this should be OK as the ratio is the same, same side as my current but feel free to correct me anyone! Final Drive 32/11 K7/1 7712569-02 Rear Wheel Drive BMW R1200GS K25 R1200ST

UPDATE: BMW have come back after just calling direct and being transferred around.
£1333.34 +vat, the part number is 33.11.7.726.889 for reference.

Ouch.
 
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Not knowingly - tl;dr of my OP is I'd done an FD + transmission oil change, felt something off and found the FD had no oil in - 100% absolutely did put it in, torqued the drain bolt to spec and couldn't find sign of a leak but seems it may have.

So yup, utterly banjaxed.


I used Putoline SP Gear oil (75W-90) which apparently should've been absolutely fine, as saw others had been using it for their FD/Transmission oil changes and saw no reported issues or concerns with it. No idea if this means I *did* pick the wrong oil still, somehow, as i've since been told I should try using Rock Oil 75W-90 instead?

I have been scouring the place and while there's some options looks like my best bet currently is one in Germany - BMW are giving me a run around to chase from one Motorrad place to another and we all know they'll likely charge a Liver and Kidney for it but I figured it didn't hurt to ask!

Ideally looking for a vented one from 2009 onwards that'll be compatible, which the German one is.

Edit: This is the one I'm currently looking at - unsure if links are allowed or not but if so happy to remove. I believe this should be OK as the ratio is the same, same side as my current but feel free to correct me anyone! Final Drive 32/11 K7/1 7712569-02 Rear Wheel Drive BMW R1200GS K25 R1200ST

UPDATE: BMW have come back after just calling direct and being transferred around.
£1333.34 +vat, the part number is 33.11.7.726.889 for reference.

Ouch.
Ask for discount
 
It does not matter what viscosity of oil what does matter is the specification

BMW transmissions require GL5 specification

Cleverer people than I will come along and tell us all the ins and outs but basically GL4 or GL4/5 hybrid does not have the correct shear strength to protect the drive gears
 
Ask for discount
Aye, I'd rather keep most of my liver as part of that transaction. Allegedly comes with at least a year if not two's warranty though.

It does not matter what viscosity of oil what does matter is the specification

BMW transmissions require GL5 specification

Cleverer people than I will come along and tell us all the ins and outs but basically GL4 or GL4/5 hybrid does not have the correct shear strength to protect the drive gears

That may well be where I came undone then - just considered it a bit whack given the service kits for the FD/Trans seem to be either Castrol or Putoline so seems a common choice that can't be too far wrong.

On a side note, I have come across some potential replacements, but the ratios are different. Rather than 32/11 it's 33/12, or 31/11 - seen some chat about the differences and it seems to boil down to easier higher-end speeds rather than as much control at lower ones?
 
I would check that the different ratios / crown wheels have the same tone ring (cut into the crown wheel) as this will effect the ABS / Traction control if fitted.
 


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