just bought 3 of these…

possible the best mod i have ever seen, replaces your vomiting mushroom gearbox breather with a banjo bolt and barb fitting that you then add a length of hose to

You can then get a whole litre or more of oil into your gearbox and keep it in there.

Done 150 fairly hard hot miles on TT and V35 and not a drop of oil has come out. Â Slightly over filled both boxes with ep85/140 and lovely and quiet with far better changesÂ

I took the breather out of the gearbox on my V35ll to see what I could do about the oil being blown out, when the breather was removed there was a spring and small ball bearing in there I’m not sure what they are supposed to do so my question would be can I run the bike with them removed and replace them with the remedy you suggest.

That locks the gear change  selector drum in each position. Do not remove, gearbox may then be able to jump out of gear or drum won’t be in correct position for next gear change or gear not properly selected in the first place. (I’m assuming this spring and ball mean the same thing as on the big blocks.)

31 euro, Christ! Â You could make that for less than a tenner!

True but get the length wrong and you will mess the pre load up. Â 31 Euro sorted my bike and happy to support tlm

It’s ok I can use a rule and vernierÂ

I seem to remember you can use the breather from a Tonti Guzzi gearbox to replace the “vomiting mushrom” (brilliant description btw).

Thats a good point Gwen, but it depends on the airbox you have, my v65t has the factory one and there is no space for the big block breather barb

So the 90 deg banjo works really well

If you have pod filters the big block breather will fit Â

Just to clarify… is this in the top of the gearbox and attached to the breather arrangement? If so it’s a non return valve (Guzzi manual calls it a ‘vent plug’). The ball bearing needs to move freely to allow the breather to work.
All the best

Yes I took the breather out to see why oil was continuously being blown out and as far as I could see it was clean and nothing obvious to cause the oil to be blown out.
The mod Guzzi35 suggested would seem to be the solution but if that spring and ball is part of the selector mechanism I presume the spring and ball fits in the bottom of that replacement.

its a lovely solution, so impressed i have fitted it to my 3 gearbox’s

there is no ball bearing under the breather on a small block, just the detent pin and a spring.
 all 3 of my bikes ( even one with 4000 miles from new) puke oil out when filled with the correct amount.


This kit is a direct replacement for the breather, you leave the spring in the boxÂ

I came up with my own solution to the mushroom breather problem , I removed the hat from the plug then made an extension to insert into the top of the breather by using a length of 3/8th brass dowel with a 1/8th hole drilled down the centre turned down in an electric drill to a size that fitted snugly into the top of the breather then connected a length of hose directed upwards and forwards so that it emerged just above the bottom rail near the footpeg never had a drop leak up to now about 700 miles later.
Make sure the hose is not kinked anywhere.