V65 Rocker Cover Breather Arrangements

I’m trying to reduce my V65 to be fairly minimal.

I have breather tubes from each rocker cover, into a ‘T’ piece that goes into the standard breather box behind the steering head. The lower outlet pipe from the box goes down to the sump, as usual.

I saw a Monza(?) recently that had the rocker cover breather pipes going back towards the battery - presumably venting out under the bike???

Anybody managed to simplify all that pipe work on their bike please?


I did a nice simple mod on mine


Thanks, Iain. A very need solution.

A question to everyone…

Does any oil actually get returned to the sump in a standard set up?

I take my breather pipes off every 2 years or so and find the sump return pipe is full of creamy emulsion, effectively blocking the pipe. I can’t imagine any oil actually gets through to the sump.

You can seen where I’m going with this thought…


Some does… Rest seams to leak out onto the gearbox!

Best to blow then sump return pipe through to check for blockages

My worry has always been the amount of condensation and mayo produced by the stock system

The mayo is a sympton of the bikes running conditions or lack of rather than the design of the stock system.Modify it’s design at your peril.

Stock system is awful , air filter utilisation shows the poor design

Did 30k miles on my old v50 with modified breather and pod filters. I see no peril?! As long as condensed oil can return to the sump and the breather is adequate to vent the crank case you will be ok

Looks good
Small block breather mod

Fanks Steve…

Just need 2-300 more cc and she will be perfect

THINKING AS CRANKCASE IS VENTED DO THE ROCKERS ACTUALLY NEED A BREATHER AS the oil that enters just overflows to the sump anyway so the rockers cannot pressurize

I think I agree. Even with a standard setup, the top outlet from the breather box (behind the headstock) pipes into the air filter box - which is obviously not pressurized.

Crank case is not vented on the small blocks

There are 2 vents up high on the rocker boxes and a return to the sump, sadly thats below the oil level :frowning:

Tried mine with rockers blocked and just raised breather from sump and it was like having a little oily fire hose when started …
guzzi-v352014-06-15 13:27:55