R1150GSA Gear Sensor Oil Leak

Motormed · Dec 20, 2020

I recently bought an 1150GSA from a member of this parish and have found it to have an oil leak.
Not a major one, but it's been leaking for a while according to the residue on the underside of the swingarm and back of the gearbox.

I cleaned the area well and I've been monitoring it now for a few weeks (the bike's garaged at the moment).
The one place where I can see oil seepage is at the gear sensor switch (pictured).
It takes about a week for a drop to form. No doubt in use and warmer weather it will leak at a faster rate.

I've poked around the forum for answers but can't find any relevant info.
Does anybody have experience of changing the switch shaft seal?
Can it be changed without removing the swingarm or is that wishful thinking? :nenau

Ian J Hartley · Dec 20, 2020

Looks like your shaft seal item 4 is weeping slightly.

A little bit of oil goes a long way and always looks worse than it is.

Welshman · Dec 21, 2020

You can probably in theory change it with the swing arm in situ, but you need to be a part time gynaecologist. :beerjug:

Motormed · Dec 21, 2020

Welshman said:
You can probably in theory change it with the swing arm in situ, but you need to be a part time gynaecologist.

Thanks for the suggestion, but my experience in that field is very much on an amateur's basis :beerjug:

ynotbiker · Dec 21, 2020

Get a cable tie up around the pins am sure comes off this way

DrFarkoff · Dec 21, 2020

motomadmed said:
I recently bought an 1150GSA from a member of this parish and have found it to have an oil leak.
Not a major one, but it's been leaking for a while according to the residue on the underside of the swingarm and back of the gearbox.

Okay Just drain the gearbox and put something like EP 90 GL5 specification in

When you drain it note the volume and viscosity Is it very "thin"

A few folks use a 75W Fully synth and it may just be giving the seals a hard time !

For the price of a litre of EP90 GL5 spec gear oil Its a whole lot more sensible than trying to get down there and pull the switch off and poke the seal out!!

I can take you photos of what its like I have a 1150GS box on the bench just now

Motormed · Dec 22, 2020

Thanks for the cable-tie tip ynotbiker.

DrFarkoff, thinking outside the box there with oil viscosity, I like it.
I'm going over the bike and servicing it at the moment but have held back on changing the gearbox oil.
I could quite easily try some EP90 instead of the 75 that I've bought. If it still leaks, I could just drain it out and use it in my MZ's gearbox!

If you could, a photo of that area with the seal in situ would be a massive help.
I've only managed to find diagrams such as Ian's in post #2, and you don't get an idea of how much the seal's recessed.

Thanks for all your suggestions so far, fellas.

Motormed · Jan 2, 2021

Well I tried EP90 in the gearbox and the leak persisted so I decided to test my gynaecological skills and go about changing the seal without removing the swingarm.

After removing the exhaust T-piece and silencer, I gained a bit more access to the area.
Ynotbiker's cable tie tip on the spring clip worked a treat to remove the switch body :beerjug:

.

I then carefully drilled a small hole with a Dremel before screwing in a small self-tapper.
I ground a notch in an old screwdriver to lever it out but the screw pinged out. Other methods of hooking and levering have also been unsuccessful. Frustratingly, I'm now left with a slightly mangled little bastard of a seal that doesn't want to come out, FFS!!

I've now resigned to the idea that I'll have to remove the swingarm in the hope that easier access will be my friend in getting the little bugger out. Changed a few oil seals over the years but never had one fight me like this before! :nenau

Welshman · Jan 2, 2021

try another screw, worth a try, my other profession is marriage counselor. :beer:

Motormed · Jan 5, 2021

Where I'm at now:

I'm in the process of removing the swingarm to gain better access to the pesky seal.
At least it'll provide an opportunity to check the pinion bearings, grease the driveshaft splines and whilst I'm at it, I'll replace the output shaft seal as well.

I've read up a few previous posts on the procedure so am aware of the need to heat up the pinions to release the threadlock etc.
Heatgun and IR thermometer on their way as well as the special 30mm socket with 12mm hex driver.

Wish me luck!!

Welshman · Jan 6, 2021

I hope you are doing it indoors, I believe its a bit chilly over there. :beer:

Motormed · Jan 6, 2021

Welshman said:
I hope you are doing it indoors, I believe its a bit chilly over there.

O yes, it was nice and cosy in the garage earlier whilst the temperature was plummeting rapidly outside in the subzero zone.
I've worked outside and in cold, damp and draughty garages or sheds in the past.
Those were the days, character building of course!

Welshman · Jan 9, 2021

motomadmed said:
O yes, it was nice and cosy in the garage earlier whilst the temperature was plummeting rapidly outside in the subzero zone.
I've worked outside and in cold, damp and draughty garages or sheds in the past.
Those were the days, character building of course!

Been there done that, no thanks, its 17:15 here and 29C off to the swimming pool with the Great Danes now, they need to cool off. :beer:

Motormed · Jan 10, 2021

Welshman said:
Been there done that, no thanks, its 17:15 here and 29C off to the swimming pool with the Great Danes now, they need to cool off.

Bit too hot for me and I wouldn't like to share a pool with some Great Danes either! Each to their own as they say :beerjug:

Motormed · Jan 10, 2021

After removing the swingarm, and with much improved access, I drilled a couple of fresh holes in the seal.
I inserted a couple of 3mm self tappers, then pulling hard with a couple of vise-grips, the little bastard came out :JB

.
Following a good clean-up of the bore and applying a bit of grease, I tapped the new one in using a 12mm socket.

Job done.
Well, sort of. After stripping the swingarm down, the FD pinion bearings are notchy and I'm replacing the driveshaft seals at both end.
However that's another story.

Sorting out that little oil seal has resulted in me learning a lot about my new 1150.
Very grateful to everyone who's posted in the past about swingarm and FD removal, I did my research before tackling the job and so glad I did! :beerjug:

Welshman · Jan 11, 2021

She looks very clean and corrosion free for a UK bike. Where in Wales are you? :beer:

Motormed · Jan 11, 2021

Welshman said:
She looks very clean and corrosion free for a UK bike. Where in Wales are you?

Yes, I've given it a good clean and addressed some corrosion (mainly on front of engine).
I'm near Betws y Coed, whereabouts are you from?

Welshman · Jan 12, 2021

motomadmed said:
Yes, I've given it a good clean and addressed some corrosion (mainly on front of engine).
I'm near Betws y Coed, whereabouts are you from?

I know Betws, I am a Border area third generation Welshpool boy, left there 40 years ago, still have family there.

R1150GSA Gear Sensor Oil Leak

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