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All engines do that, its why they have a breather fitted. Some vent to atmosphere (bad) and most recirculate the vapour back into the engine.
 

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Discussion Starter #7
Crankcase pressure reduction means easier movement of crankcase means smoother rotation means more power and less engine brake :)
 

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I could never stand the plastic separator thing, and I was planning to design a part and get it fabricated at a local machine shop, but I came across your post. Where did you get it from exactly? I could't find one for myself.
 

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A lot of bikers fit similar devices (or make their own as I did on my Buell XB12) and go hand in hand with catch cans. Basically all the nasty oily vapours produced in the engine are sent back into the intake system to be burnt rather than allow them to polute the atmosphere. Trouble is with large capacity single and twin cylinder motors running a modern lean mixture when they stumble its like riding a bucking bronco! So we stop the crap going back into the intake and tweak the mixture by some means :rambo:
The oil is either diverted into a small catch can or simply dropped onto the road. I just had a rubber pipe from the cylinder head that went into a little mini conical air filter (nothing as intricate as your valve). The general concensus amongst Buell owners is that it does help the situation and it definitely stops the air box and filter from getting gunked up with oily goo. How much blow by oil goes through the system? This video shows a catch can set up:-
www.youtube.com/watch?v=3KrSn3BoeLE

Venting direct to atmosphere.........not something to do if you vote for the Greens!


DIY version (the yanks love these things!)
www.youtube.com/watch?v=7muQTkXBkEs

Looks like your device just vents to atmosphere via a reed valve?
 

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I have run a filter, venting to the atmosphere on a 147 1.6 ts 105 hp and some vapours got into the cabin and ot smelled pretty bad, since then I fitted a catch can. Anyways you can't do anything on the multiair engine since it doesn't have a normal push on fitting.
 

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Discussion Starter #16
well, I had to remove it temporarily, and boy am I glad that I could reinstall it :) I can´t recommend it enough (although it is very expensive outside of Japan). The engine really spins more easily, power all the way along the whole rpm range, simply amazing.
 

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I'd need to see before and after dyno results before I'm convinced.
It's a good idea to improve crank case breathing. But if it genuinely improved power and torque as being suggest, manufacturers would have fitted them from new. After all it is a pretty cheap "fix".

I have seen some systems which use an "extractor fan", in conjunction with a catch can. The idea being to have the crank case under a slight negative pressure.

When I get my Q4 back on the road I think I will look to do something about this, certainly if it helps clean up the treacle - like residue that builds up in the 159 heads. It seems a common problem.

However, it is one thing to relieve crank case pressure an quite another to claim dramatic improvements to power r/torque. Proof positive will come from Dynamometer plots, so evidence please! But the device certainly looks like an improvement on what is Standard.
 

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Discussion Starter #19
Sorry, I am not able to give you any plots. Don´t have the equipment for this.
BTW, the reducer is also available for the 916 spider, 156er and so on...
 
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