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Discussion Starter #1 (Edited)
Hola friends,

I was doing a more thorough cleaning of my 1000DS and decided to pull the breather box. Some of you may have found some milky goop inside the oil filler cap, the same stuff that accumulates on our oil sight glasses. Well, the breather box and hoses were full of that gunk. I doubt they've ever been cleaned. The stuff inside the breather box was yellowish and had a faint smell of gas.

I think the goop has accumulated in there over the years, as it is occasionally subject to shorter distance riding - where condensation and blow by fumes are not allowed to evaporate.

I could blow air through the system so it was not completely clogged, but if left unattended I would imagine the gunk would prevent the breather from doing its job.

Anyone else experienced this?

PS. My oil doesn't look like this
 

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It's called an oil-water emulsion. Shorter rides that allow water condensation to accumulate in the crankcase is a common cause. A leaky water pump seal or head gasket that allows small amounts of coolant to enter the crankcase are also causes — but less common.
 

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Discussion Starter #3
It's probably not an issue as long as short trips are kept to a minimum. However, just out of curiosity, I'd like to know why it is so common among Ducatis - my previous bikes from other manufacturers also had sight glasses but no pigeon shit in them. Also none of my friends who ride japs are familiar with this phenomenon. I know that the gunk vanishes after a good ride, but since I'm probably going to stick with Ducs I'd rather know what is happening in our engines and why - in this case, whether the milky sight glass/breather assembly is just a Duc thing and if so, why?


Thank you!
 

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The problem is from short rides in cool, humid weather and a long breather system that lets the vented air cool quickly. Most of the 4cyl. bikes breathers are close to the bulk of the engine mass and they stay hotter. They usually vent off the top end of the engine and the pressure pulses are less sudden so less oil is carried out of the crankcase vent valve. The pressure pulses on a big twin move lots of air and oil gets carried with it out the breather because of the smallish volume of the case and all the bits spinning about.
 

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The problem is from short rides in cool, humid weather and a long breather system that lets the vented air cool quickly. Most of the 4cyl. bikes breathers are close to the bulk of the engine mass and they stay hotter. They usually vent off the top end of the engine and the pressure pulses are less sudden so less oil is carried out of the crankcase vent valve. The pressure pulses on a big twin move lots of air and oil gets carried with it out the breather because of the smallish volume of the case and all the bits spinning about.


Thank you, that sounds logical. Took her for a 200 km ride and found no goop nor water in the system.
 
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