Rear Drive Oil [Breva 1100]

What do people use?
Changed mine recently as part of a major service but have had a slight leak since. Difficult to say exactly where it’s coming from. I removed the wheel last night and gave the whole area a thorough clean, so after the next ride I should be able to spot the source. I think it might be the seal.
Just wondering if I’ve used the wrong oil. I used Castrol EPX 80W-90 for both the drive and gearbox. This was recommended by Crossan Motorcycles in Belfast - a regular supplier I’ve been very happy with in the past.
[Apologies if this turns into another oil thread!]

You need to “Burp” the rear drive…
Take it out for a run when the rear drive oil is warm take out the filler plug and let the pressure release and re-tighten.

It works on the early rear drives not sure on the newer bikes!!!

There are some threads on this site about “Burping” the rear drive…
Regards Jamie

Ta for the reminder!

R80’s got a little breather vent built into the filler cap for that reason

Kerry might be level plug leak? Can easily end up on the bottom edge of the flange from there

Thanks for the suggestions guys. I’ve read a number of threads about oil leaks in this area, but hadn’t come across burping! The Carc has a pressure vent so probably not the problem.
Some threads suggested that some oils were more prone to ‘‘weeping’’ at the seal than others.
I was wondering if any members had experienced this, and what oil they used.

in the bevel box Hypoy sae 90 in older bikes with molyslip, stick to reccomended, and run it up then “burp” it.

Gearbox is also hypoy but you can use the sae 80/90 .

V50 IS different …if in doubt take a look in the manual, NOT got a manual look on the "greg Bender website just about every Guzzi manual both service and owners handbook available to download free there.

To be fair if you search the net you can find just about all car and bike owners and service manuals and for cars “how to” guides

I recently downloaded FREE the Suzuki Jimny and VW Passat service manuals and the “how to” change the electric window bowden cable in the VW Oassat all with a vdo guide made it very easy to do and the part was £14.99 as opposed to £70 for 2nd hand door card and megga bucks new parts.

Kerry Blue,Why go with what they recommend? Have you consulted the owners manual - the one I’ve just had a look at for a 2005 Breva 110 online says 85W-140.Might be best to stick with the manufacturer’s specification and use the heavier oil. GJ

First possibility is a blocked vent. The leak from mine healed for about four months after cleaning Secondly, the seal, which wnt at about 18,000 miles. Try Eriks, they are considerably cheaper than OEM.

Also check that it is not air box drain which was my problem with blow out oil running along the speed sensor cable which made it look like a carc leak.

85w150 is the wrong oil for a carc. The manual is wrong and has been updated

The manual definitely says 80W-90 for the Carc. I think the 750 Breva uses 80W-140.
Hadn’t considered a blocked vent - will check.
And thanks for the other suggestions.

Yes - the ‘little’ Guzzis use the heavier oil in the drive box (I do not recommend trying to get some in Clermont Ferrand!).RS

My oil leak is definitely coming from the seal. So new seal needed. Eriks was mentioned above as seal suppliers. Anyone know where can I contact them?

Get a seal from either Spares GB or if you know what seal you need then a bearing supplier take a gander in non oem thread it is there page 3 just keep looking on there

Also this advice:-

The Guzzi part spec. is 85(I/D) x 110(O/D) x 8(Width) BASL

(BASL specifies the type of seal together with a back-up dust seal)

I found it next to impossible to match the width of 8mm but 10mm is easily available and fits OK.
It is important to get a viton seal in order to handle the temperature range encountered.

I hope this helps
Kenguzzibear2012-01-16 19:40:18

Ken , that’s great.
I’ve actually sourced a 10mm wide seal locally this morning.
That extra info will be useful when I go in to collect it.

Should be back on the road in a couple of days!

Many thanks,


just remember to burp the bevel box after you have fitted new seal and on firts run it will save oil getting out , it is an old Guzzisti trick, put it this way in all the miles my old V1000 has done I have only replaced this seal 2 times in 20+ years

The Carc on mine has a vent, [which is not blocked - I checked], does it still need to be burped?
Maybe I’ll do it anyway. Better be sure!

Ah it’s a CARC, not an old big-block


So-o, shouldn’t then. You may have been right first time about a seal

Well, I finally got round to changing my seal. I got one locally from a bearing and seal supplier. It cost a mere €10! About half what the local BMW dealer wanted. It wasn’t a Viton seal as suggested by Guzzibear but they assured me that it was rated up to 100 degrees C, which I reckon should be fine for the Carc.I’ve done about 200 mile since the change and no sign of any oil leak.So, fingers crossed!

What oil did you use in the end, KB? My last oil change on the CARC was when Corsa Italiana renewed it under warranty and they put 80w90 in. Guess it will need changeing soon.Cheers, Gerry.

I used Rotra MP SAE 80w-90 Transmission Oil [£8 for 1 Litre]. This was reccomended, and supplied, by Gutsibits. Those guys are incredibly helpful. They reckon this is the latest Carc oil reccomendation from Moto Guzzi. Tom.