FD breather M20 Cali' 3

The breather on my California 3’s FD, is missing the rubber insert, that is still in place on the gearbox breather. As a design, compared to my BMW & Yamaha it seems poor.Two questions:1) Where can I get a replacement rubber insert? Or any alternative?2) Anyone know of a breather that is better designed that will fit.I’ve not removed it to check the pitch of the thread, just read that it’s M20.Ta

Ah, after reading your post yet another time, I have at last worked out what you are asking.The breather on the bevel drive has no rubber insert, it has a metal cap to cover the hole.The gearbox breather normally has a tube fixed to it which goes up higher on the bike to stop oil being ejected. The term California III FD normally refers to the fully dressed version of the bike, with fairing.
Brian UK2012-11-02 09:10:52

Is the OP actually referring to ‘breathers’ or just the rubber inserts that fit into some of the filler plugs to prevent crud and corrosion bunging the hex up?Does the Cali III actually have a bevel box breather as standard - small blocks yes, but big twins?I thought it was just a hex socket plug, unless an aftermarket breather has actually been fitted.

guzzijack2012-11-02 10:26:36

I think GJ has it right.
In which case burping will be required.
get the bevel box warm after a decent run, unsrew filler cap then srew it back in to create a partial lower pressure inside the box.
Reboot etc may supply the bungs if motmecca cannot.

You’re right, there is no breather on the bevel box. I’ve never found “burping” neccessary on the Tonti bikes as there is the rubber bellows which allows some expansion.

photo time. back shortly. FD for final drive? Didn’t realize it had another meaning in Guzzi circles.Hmm, never had this problem loading photos onto a forum beforeNever make assumptions!!! My three other shaft drive bikes all have breathers fitted to the top of the Final Drive. Looking at this plug, I made the assumption that it was a poorly designed breather. After having just removed it, I can now see that, what I had perceived as being a hole through the plug. It is in fact just burrs left behind by the broaching process creating an illusion that there was another hole underneath. Odd though, other manufacturers fit breathers in the final drive, why not Guzzi?

1150GS2012-11-02 14:47:36

Only on the Cali 111 FD which never really took off.
Full and heavy fairing which affected the handling and forks badly.
Looked good though.

A couple of reasons.On the vast majority of Tonti framed big twins the bevel box has enough overall capacity v oil volume to cope with expansion when hot. So no need for a breather.The second reason is that the unit is not truly sealed where it joins the driveshaft - apparently, (according to Guzziology), on the earlier big twins with a smaller capacity drivebox and under fully loaded conditions, it sometimes happened that oil would migrate up the swingarm and even make it’s way past the gearbox output seal!The smallbocks have a smaller ratio of volume to oil in their bevel boxes, so a breather is required.The big twins with the exposed driveshafts and the totally sealed bevel boxes, (the spine framed models), do not come with a breather as again the volume should cope with expansion. However, particularly for those bikes and, as Ian has mentioned others can benefit, it’s advisable to ‘burp’ the box when hot as it then creates a negative pressure and can eliminate small weeps past the seals.

Thank you all.