Engine breather

If you need technical information or help with your BOSCH ignition squarecase Ducati 900SS - Darmah engine - post your FAQs, comments & questions here.
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duck-a-tye
Mariana
Posts: 42
Joined: Fri May 28, 2004 2:52 am
Location: Australia

Engine breather

Post by duck-a-tye » Sun Apr 12, 2009 5:42 am

Hi
What do you guys run as a engine breather tube on Darmahs? Mine has the large tube off the plastic breather cap, which runs up under the tank, but nothing else.

Cheers Tomo

garryc
Parallel Twin
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Joined: Wed Dec 26, 2007 4:53 pm
Location: Forster NSW Aust

Post by garryc » Sun Apr 12, 2009 5:47 am

My piece of garden hose runs up under the back mudguard and is cable tied to ther frame

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abmartin
SSD900 Darmah
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Location: New Brunswick, Canada

Post by abmartin » Sun Apr 12, 2009 9:31 am

Mine just goes open to the atmosphere as well since the under-seat collector for my bike is missing. I recently put a small air filter on the end of the hose but I'm not sure whether it actually serves a purpose.

Bruce
1979 900SS
Fredericton, NB
Canada

wdietz186
Cagiva Alazzura
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Post by wdietz186 » Sun Apr 12, 2009 11:42 am

The filter on the breather is a good idea.The engine inhales thru the breather when the pistons go up the bores and exhales when they come down.On the stock setup which everybody has removed the breather was routed inside the air filter housing.The little flap thingy at the end of the hose in the housing was intended to stop the inhale part of the cycle and reduce positive pressure in the cases which will also push out oil at high revs.A reed valve or one-way valve from an automotive air injection system works great as a substitute and can reduce the potential for oil leaks.

duck-a-tye
Mariana
Posts: 42
Joined: Fri May 28, 2004 2:52 am
Location: Australia

Post by duck-a-tye » Mon Apr 13, 2009 2:21 am

I came across a crankcase breather on ebay sometime back, it was for old british bikes I think.

The idea was it caused a vacuum in the crankcase, not pressure. Is something like this ok for Dukes?

Tomo

Lumpy
SD900 Darmah
Posts: 327
Joined: Sun Mar 25, 2007 5:49 am

engine breather

Post by Lumpy » Mon Apr 13, 2009 5:04 am

Sounds very similar to the set-up that wdietz186 is talking about. It all comes down to making negative pressure in the crankcases and inhibiting oil leaks. Rather than pay good cash maybe go with wdietz186 idea and get an old PCV valve and mount that on the breather tube. These are a very basic non-return valve or one way valve and you could perhaps mount one in the breather tube in such a way that would allow the engine crankcase gases to blow out but not suck in. You could pick up one of these valves from an automotive wrecker for nothing or very close to nothing. Certainly got me thinking, I`m going to ditch the bit of rag cable tied on the end of the breather tube and bung in an old PVC.

duck-a-tye
Mariana
Posts: 42
Joined: Fri May 28, 2004 2:52 am
Location: Australia

Post by duck-a-tye » Mon Apr 13, 2009 8:59 pm

an old pcv valve will be easy to find. and I've ordered a breather filter off Steve, so I'm covered both ways

Cheers
Tomo

wdietz186
Cagiva Alazzura
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Post by wdietz186 » Tue Apr 14, 2009 11:57 am

If you use a pcv get the largest you can find and mount it so it is vertical as most use gravity as a closing method.

stian buksa
Cucciolo - the Lil Pup
Posts: 20
Joined: Mon Oct 12, 2009 11:50 am

Post by stian buksa » Mon Oct 12, 2009 1:12 pm

Anybody tested guzzino.com`s Baffled Aluminum Racing breather box ?

http://guzzino.stores.yahoo.net/albrbox.html

I wonder if this is even better than the K&N filter on the end of the hose...
Pricier though
Is it still necessary to put a filter/valve at the out end of the tank ?

wdietz186
Cagiva Alazzura
Posts: 703
Joined: Sun Sep 10, 2006 5:40 pm

Post by wdietz186 » Wed Oct 14, 2009 6:14 pm

If you want to get all fancy and hang bling on it go ahead.The catch tank is good for racing as most orgs. require one and constant high revs will tend to push some oil out but on the street a hose and a filter is all that is needed.

Elliot
Cucciolo - the Lil Pup
Posts: 20
Joined: Tue Apr 18, 2006 10:19 am
Location: Christchurch, New Zealand

Breather Filter

Post by Elliot » Sun Oct 18, 2009 2:12 am

There is a nice little K&N filter which fits directly to the breather stack. I think it is off a turbo blow off valve. Does away with the hose completely and stops sucking dirt off the rear wheel!
Owner of two 78 Dramahs as I can't afford a 900SS or a Greenframe!

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