Gear oil on wheel rim

Getting splatters of oil coming out from bevel box on to the wheel rim.

Engine and gearbox are leak free , added a drop of molly to the gear oil and the splatters became molly coloured, breather is clear and allows air to pass so i’m assuming the output seal has started to fail, how easy is the output seal to change?

What oil is in the drive box?

Ep85/140 just changed it!

That’s a very convenient coincidence, are you sure it’s simply not overfilled?

Are you sure it’s actually coming from the seal (hav e you looked)?

I’m not too familiar with the small-block FD’s so just guessing really…

changing the seal is not a job I have done for a long time, but I do recall that you do have to make sure the whole area is clean whilst doing the job and the area where the seal sits has to be even cleaner. other wise you risk having to redo the job. you could check your local bearing shops for the seal, but be aware that with the vast number of internet companys selling seals/bearing etc from all over the world, you will find there are some good and some crap seals around, be carefull out there.

Mine does that, easy to overfill the BB at service, thermal expansion squeezes it out of the drain plug, never mind the useless breather. Am currently in a period of shiny, dry rim, compensated by mysterious oil drops under the engine. So, yin and yang in perfect balance there :sunglasses:


it was leaking when i got the bike, changed to make sure it was 85w140, drop of molly to colour it to make sure splatter was from diff. Â Deff not over filled, oil coming out between the bevel box and wheel hub.

Take it its a case of spotlessly clean and carefully prise seal out then tap new one on in?

going to be a pain as it does not have a main stand!

If it’s like a big-block one, yes.

I’m still not sure how the shrouded brake disc fits in with all this tho (literally!)…

Appendix ~ did my 850 Tonti one again in 2013 as it had developed a slight weep again; the hub centre does have a bit of scouring damage where the seal runs, so is most likely the reason why, but the new seal I got had an extra lip on the outside presumably to discourage dirt and sh1t going further into the actual seal part. Which I think is very neat … doesn’t leak either!
The seal came from Gutsibits

how easy is the seal to change on a small block?

brake disk is on the other side of the wheel on my TT ( different to the v35 monza)

We-ell, to do my last one on the 850, lots of welly with big screwdriver to get the old one out, new one was tapped in with a hammer and drift.

But that assumes your’s is also accessible from the outside of the casing. (?)

I replaced mine a while back on my v50 and it wasn’t easy (more of a pain), The main problem was getting it all apart which needed the use of a puller and some home made bushes/blocks as it was all extremely tight and I didn’t want to damage the cast housing, Also take great care when re-assembling it all, even though the gears are shimmed mine went too tight on the pinion gear when I applied too much force seating the other gear on the shims, it was easily sorted by backing it off a little by using the pullers again.
But I got there in the end :smiley:

if after removing the drive box and looking inside you are not sure that you can do the job pay someone to do it for you, if poss ask for advice on this forum or at the local Guzzi club branch (if you have one) re the best place to take it, it is a job you dont really want to get wrong…

Seconding that really - when the box on my V50 started leaking I just unbolted it and sent it to Nigel at NBS. Meant I got it all inspected at the same time too.

I am part way through doing this job myself, see "Breva 750 Bevel Box Output Seal " on this same forum.

So far I have got it apart and got the new seal in. Next I have to get the roller bearing inner race back on but don’t have a suitable sized tube to drive it on with.
Good luck with yours, whichever way you go.