Leaky rear end...

[DucatiPete]

Hey y'all,

I was lucky enough to get a few days off last week. The weather looked promising so I took a quick spin over to South Australia. I covered an easy 1800ks over three (relatively serious) riding days.
It all went very well, especially the day spent winding 'round the Great Ocean Road... Sure it was a little warm (~mid 30s C), which can be a bit uncomfortable behind the RS fairing, but such is the current climate...

The only bike-related issues were:
1. A front puncture. No drama, really. I noticed it while at a service station after a lunch break. I had it patched by a local (auto) tyre shop and was underway again in less than an hour... (I have a question about this puncturing issue but I'll raise it in another thread).

And, more to the point of this thread:
2. A leaky final drive.

This pic was taken after the trip so shows how bad it got (ie not too bad). It doesn't actually drip (when the bike is stationary). It's just sort of (heavy) misting/dribbling (if you know what I mean), coming from the axle hole. I thought the FD may have been overfilled, but on inspection I discovered the oil was approx 10mm below the threads of the filler plug hole. The (FD) oil is fresh Castrol 75/140 synth. By the look of the rear wheel this 'leaking' has been happening for some time (I am only a recent owner of this machine).
A couple of questions:
1. I'm guessing the internal seal is at fault so I should order a rebuild kit and plan on a day's action in my shop?
2. (As I'm planning to do some riding before the above mentioned diff job) I should top up the oil in the diff in the meanwhile (ie to the bottom of the threads)?
3. Is there anything I'm missing or should be aware of before tackling this little jobbie?
TIA
pete

[Duane Ausherman]

While replacing that seal, I would also replace the one at the front of the pinion and seal it up. That one has 3 paths for oil transfer.

You don't really need to top it off. All you care about is that the ring gear is in the oil, as it will splash around perfectly well.

Getting that bearing out to replace that seal out can be a tiny bit tricky.

[SteveD]

In the meantime Pete, I'd wipe the tyre with shellite to remove the oil. You may get damage to the valve covers otherwise. Damhik.

[Major Softie]

The title of this thread is rather unfortunate considering the age of many of the members of this group....

[ME 109]

The title of this thread is rather unfortunate considering the age of many of the members of this group....

Ha! Speak for yourself Major!
Oops! gotta go.....

[2valve]

hi to all , im no BM guru , but how thin is the synthetic gear oil V'S the 90Weight dino gear oil ? would it be worth a try to dump the synthetic out and refill with dino oil ? and see how it goes .

[SteveD]

hi to all , im no BM guru , but how thin is the synthetic gear oil V'S the 90Weight dino gear oil ? would it be worth a try to dump the synthetic out and refill with dino oil ? and see how it goes .

Be worth it for the cost of the trial. Others have said that's worked for 'em if the same thing happens in the engine. Synthetic might be overdoing it for the fd maybe?

[2valve]

hi steve , bought some synthetic gear oil to try in the BM , BUT when i actually poured some out to have a play it ,it was like water so thin ( 75 /90 W i think ) ,so now the container is sitting in the cupboard never to be used ?

[SteveD]

hi steve , bought some synthetic gear oil to try in the BM , BUT when i actually poured some out to have a play it ,it was like water so thin ( 75 /90 W i think ) ,so now the container is sitting in the cupboard never to be used ?

Howdy Gary.
I'd go half and half in the gearbox. Isn't that how they make semi-synthetic anyway?

[2valve]

not sure steve with the oil ratio blend that penrite makes ! so i bought some semi synthetic and its seems to be a "lot" thicker than the full synthetic stuff. this way atleast i can compare when i do mix the stuff together . off the topic a bit scored a good price on 2 x 20ltr's HPRGAS 10 oil that you youse in your BM, container reads full zinc so hopefully all will be well with the oil its a lot thinner than what i was using before.