R80GS - Transmission problem

[sidestand]

Was out riding my R80GS this morning & went to fill her up -
when I'd paid & got back to the bike, I noticed a patch of oil by the rear wheel.
It looks like it's leaking transmission oil - it's all around the drain bolt, but that seems to be on tight.
As I was only a couple of miles from home, I rode it back very slowly - there is a bit of oil on the back wheel, but no drips on the drive - maybe most of the oil has gone.

Anyone got any ideas what might be wrong before I get the Haynes manual & spanners out ?

It was stood for ten years before I rescued it - so could it be perished seals ?

 

[John Armstrong]

Guess you need to narrow down what's leaking. Does the mono have seperate oil for the drive shaft and final drive? If they do I'd check the fluid levels to find the culprit.

I'd guess the seals will have taken on a "set" if not moved for 10 years, probably worthwhile looking at which other ones might be at risk too if you're going to be stripping the ar5e end down.

 

[(RIP) Proff]

I'm thinking he maybe has a paralever if so could be his main seal blown and it drips down to the drain plug

 

[Rob Farmer]

Sidestand has a Paralever 80 if I remember correctly from the pictures he posted a while back.

Whip the rear wheel off and see if there's anything obvious round the seal.

 

[sidestand]

Thanks for the quick replies folks.
Rob is right, mine is a paralever.
I'll get leafing through the manual tonight & whip the wheel off for a look tomorrow. I'll also check the fluid level, although I'm pretty sure it will be almost empty. That blown seal theory fits the facts

Then it looks like an order off to Motobins ......and there was me thinking this was going to be much cheaper motorcycling than running my K12

 

[Rob Farmer]

Try leaving a 12 standing for 10 years and see what the bill would be

 

[sidestand]

Just the thought of that makes me feel faint Rob
There would be at least two dozen software upgrades to do for a start

 

[John Armstrong]

I'd whip the rear gaiter off and see what comes out as my para gearbox was set up for a mono and was happy to vent excess gearbox fluid down the transmission tunnel ..................

 

[sidestand]

I was thinking of checking the gaiter in any case John, as my Haynes manual doesn't show any kind of O rings or seals to keep oil in, apart from the gaiter - so it is currently prime suspect for the problem.

 

[sidestand]

I've taken the back wheel off - no sign of any oil inside the hub/brake assembly.
Checked over the gaiter - no issues there
Also drained the oil from the gearbox - got about 175ml out & the Heynes manual reckons 250ml, although I did it cold, not hot as recommended.
It may have had only that much to start with though, as that was one thing I didn't check when I got the bike going again (too used to the 'sealed for life' one on me K )

Another mystery is that the 'oil' on my tyre & rear wheel is sticky - well the oil I just drained isn't ........so I wonder if the main 'puddle' I saw was something else I parked over & I panicked over the oil I found near the drain plug. ......there was definately some oil there though.

I think I might just refill the box with exactly 250ml as recommended, tighten everything to proper torques, clean everything down, then take her for a 10-20 mile run & drain the box down into a measuring jug again to see if I've lost any more.
If I have, I can feel a trip to Balderstons BMW for a full service & sort out coming on

 

[Rob Farmer]

Your gearbox should have 0.8L of oil in there. Needs to be at least GL5 spec as well. The bevel box has 0.26l in according to the BMW schedule - I presume you meant this when you said the Gearbox.

 

[sidestand]

Yes, I did - and I should have said centilitres instead of ml - Heynes says 25cl
& you reckon 26cl - got the replacement SAE80/90 diff oil from Halfords
main gearbox & engine are OK - did those when I got it & check them regularly.

I need to get some fork oil as well - although Heynes say this is a special on the GS forks - much lower viscosity than standard fork oil apparently.
Is this available at BM dealer/motobins only then ?

 

[(RIP) pastyman]

Just a couple of thoughts, I have known some oil blow out of the breather on the top of the diff if it has been overfilled Not usually a lot but it could run down to the filler .
Dont forger to check the earth bold on the gearbox, It doubles as a breather for the gearbox. It does get blocked and that would result in oil being forced out of the gearbox into the swingarm then possibly out through the gaiter, although the seal to the diff might be sound, a hole however small would alow oil to drip out. Does sound as if you may have simply parked over an oil slick though

 

[sidestand]

Well I put new oil in the diff (250cc is a tad too much though, as it started coming back out of the filler hole) Took her out for a short spin & no sign of any oil on the rear end. Think I'll go for a longer run before I consider the problem done with.
Thanks for all the help everyone.