Trask CheckM8...
Road Master
Joined: Jul 2021
Posts: 1,142
Likes: 2,753
From: England
I fitted a filter to the end of the breather pipe and mounted it high as possible, usually around the headstock. Never used a catch tank and never needed one. If the breather pipe is as long and as vertically routed as possible, oil vapour condenses inside the pipe and runs back down into the crankcase while air pulses escape. The filter kept dirt out rather than oil in.
Tourer
Joined: Jan 2023
Posts: 449
Likes: 302
From: New Zealand
makes sense to me although my filters mounted to the frame at the bottom, it doesn't leak oil and seem to be dry, I may change it though, when i get the new aircleaner I'm planning on fitting a catch can for the oem breather hoses(the ones that go into the aircleaner) along with this tranny cover breather
Intermediate
Joined: Sep 2023
Posts: 44
Likes: 32
From: Phoenix, AZ
I'm also looking at replacing my air-cleaner, I did consider the Trask setup too, but now looking at the Fueling BA air-cleaner which has an external breather by-pass option, I am planning on fitting this on it's 10 000 mile service- https://www.feulingparts.com/category/AIR%20CLEANERS
Road Master
Joined: Jul 2021
Posts: 1,142
Likes: 2,753
From: England
makes sense to me although my filters mounted to the frame at the bottom, it doesn't leak oil and seem to be dry, I may change it though, when i get the new aircleaner I'm planning on fitting a catch can for the oem breather hoses(the ones that go into the aircleaner) along with this tranny cover breather
Even if there's no visible oil seepage from the breather when mounted low, it's as well to keep it well away from the rear tyre so no mist is blown onto the tyre at speed.
Seasoned HDF Member
Joined: Feb 2009
Posts: 5,641
Likes: 1,985
From: Cleveland Zoo
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HDF Community Team
Joined: Nov 2012
Posts: 6,186
Likes: 2,412
From: USA
For fun, I went looking at their innards, because I was curious. Especially about their use of a reed valve.
So in a nut shell, it's a vented cover. Why they're using a reed valve instead of a mesh, I can't even guess. A reed valve sure isn't the right tool for separating oil from vapors, while generally a mesh is.
With something like this, you do need to have that hose run high and long, so that hopefully the liquid oil deposits on the inner hose walls, and drips down. Having to drip that oil back through a reed valve is not a help.
This case ventilation isn't a new technique. Folk have been doing exactly this on Moto Guzzi gearboxes for at least half a century.
So in a nut shell, it's a vented cover. Why they're using a reed valve instead of a mesh, I can't even guess. A reed valve sure isn't the right tool for separating oil from vapors, while generally a mesh is.
With something like this, you do need to have that hose run high and long, so that hopefully the liquid oil deposits on the inner hose walls, and drips down. Having to drip that oil back through a reed valve is not a help.
This case ventilation isn't a new technique. Folk have been doing exactly this on Moto Guzzi gearboxes for at least half a century.
