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Discussion Starter #1
does anyone here use a krankvent? if so, how is it? any FHE would be appreciated.
thanks,
paul
 

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What advantages are there of changing the Crankcase Breather other than appearance? I have seen many aftermarket versions, the reason I ask is that I seem to have a lot of oil 'leaking' from mine, I don't know if there is anything wrong or it is loose/blocked or whatever but recently it has been more messy than before;



I took this pic today and I'm planning to remove it all to see if I can find out why it's dirtier than normal, any ideas? BTW there is no significant amount of oil in the airbox - just around the breather, is it worth getting an aftermarket one? are they better, less troublesome than the stock one? can I get more power by changing?, other than the underseat tank system.

BTW, Sorry for the thread 'Hijack'.

:)
 

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DukeDesmo said:
What advantages are there of changing the Crankcase Breather other than appearance? I have seen many aftermarket versions, the reason I ask is that I seem to have a lot of oil 'leaking' from mine, I don't know if there is anything wrong or it is loose/blocked or whatever but recently it has been more messy than before;

I took this pic today and I'm planning to remove it all to see if I can find out why it's dirtier than normal, any ideas? BTW there is no significant amount of oil in the airbox - just around the breather, is it worth getting an aftermarket one? are they better, less troublesome than the stock one? can I get more power by changing?, other than the underseat tank system.

BTW, Sorry for the thread 'Hijack'.

:)
Krankvent? is that a name of a specific crankcase vent?

I had a Nichols one on my 853 that worked great, didn't leak a drop, and looked great. The stockers leak like crazy.

The more miles you put on, the more blowby you'll get because as your compression drops from wear, that compression is going into the cases as it bypasses the rings. Even the underseat systems suck - i've seen them crack and leak.
 

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Discussion Starter #5
the std breathers are notorious for leaks, the later plastic ones with the hex are much better but aftermarket ones look pretty. the aftermarket ones have a reed valve which work fine, but i'm going for hi-comp pistons etc, and wanted something that maintains a negative crankcase pressure.
the "krankvent" is a specific type that was originally designed for harleys and their website claims are impressive. i'm looking for some independant feedback before i buy.
 

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So what's the best then? Standard breather, 'other' breather (if so which one), no breather - just a filter, underseat oil catch tank/breather, 'traditional' style length of hose venting to atmosphere or any other idea?

I was of the understanding that venting to a tank of some sort etc increased the 'effective' crankcase volume and so gave better power? but since I've got to do something with mine (if only clean & re-seal) then I might as well do something that's an improvement.

Any reccomendations?........

:)
 

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Discussion Starter #7
your std breather is good for the bin, unless the leak is from a split hose. best bet is an aftermarket breather or a replacement std one. note, the krankvent i want to use has to be used with a std type breather as the hole in the crankcase needs filling with something.
 

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OK, sorry to bring this up again but I remembered reading something on the old site, so on searching the archives I found a link to; http://ducatisportingclub.com/xmb/viewthread.php?tid=18058 which explains various options. I don't want to go with the corsa underseat box for various reasons but am curious as to this option;

"Except for the larger oil separator volume, the advantages of the corsa system can be implemented in the stock system by hollowing-out the reed valve to remove the constriction on drainage. Alternatively, STM valveless breather connector can be used. Then use a one-way reed valve at the airbox connection. A 748RS remote breather valve works well here."

and;

"The reed valve location is good for emissions but not for engine power and crankcase breathing. What happens is that under certain conditions, under high rpm and light load, the oil doesn't run back because of the reed valve and it builds up in the tube above the reed.

The simplest solution is to hollow out the reed assembly and leave it internally open but still hitched to the volume bottle. This allows the volume of the breather bottle to perform its function and usually gives a slight horsepower increase also.

Then, use either a 748RS reed valve in the airbox at the end of the breather hose, OR, use a Ford diverter valve (in-line one way) just before the airbox."

This sounds logical to me, so what about the 748RS reed valve - presumably this is a straight-forward install?, is this a worthwile mod? any ideas of price? and the Ford diverter valve setup also sounds interesting (cheaper too, maybe?) any part no's or links to the type of Ford valve would be useful.

Anyone tried either of these options?

:)
 

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Yes, I've seen that on their website and it looks good, I am considering that as a direct replacement, but I was wondering if there's any merit in fitting the one-way valve further away from the crankcase, either just before or in the Airbox as per 748RS? or an in-line diverter valve as described on the link from the archive?

Seems logical to me that this might be a better option both for power and elimination of oil in the airbox but without going to the Corsa breather box/catch tank which involves a lot of parts/hassle/expense.
 

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If you eliminate the reed valve on the crankcase mounted breather, it will overwhelm the little OEM breather box.

I'm using the large underseat breather box, STM corsa breather (no reed valve) and the air box check valve on my 916SP. It works.

http://www.motowheels.com/italian/myproducts.cfm?parentcategoryid=6%7CCarbon%20Fiber&productID=2335&showDetail=1&categoryID=14|Ducati%20748%2D998%20CF&vendoridtodisplay=0&filterFor=&collection=168%7CEuropean%20Motorcycle%20Parts
 

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OK, when you say overwhelm, do you mean that it will fill with oil? if so is this more likely to spew oil into the airbox?

What about good old fashioned venting to atmosphere? I'm sure I've seen a 916 with a large pipe exiting by the exhausts, is this any good?, if so does it need a reed valve, a filter, both or none, I've had old bikes where they were vented straight to atmosphere and I don't recall seeing any filter or valve? If routing to airbox only started for emissions reasons, is it better, performance-wise, to not do it?

I'm not worried about emission regulations or anything like that just exploring the best option with regard to power, reliability, eliminating oil in the airbox and any other issues that might exist - From what's been said I guess the best option is the corsa box but that needs a mono subframe, I lose what little underseat storage there is and it costs alot of $$ , I assume the corsa box vents to the airbox like the OEM one?

Does anyone know what the volume of the OEM breather box and the volume of the corsa box is?

And what exactly is fitted to the 748RS?

:)

P.S. Sorry so many questions. :)
 

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DukeDesmo:

I found this explanation on Ducati Sporting Clube regarding crankvent and the use of the K&N system (http://www.ducatisportingclub.com/xmb/viewthread.php?tid=18058#pid163229). I think you were reading the same or similar post. Doesn't look like the K&N is recommended.

Here's a little blurb from Section8Superbike regarding just using the Corse Airbox Breather and a hollowed Crankcase Breather (http://www.section8superbike.com/cgi-bin/section8/flypage.html?mv_arg=22). I'm interested in knowing more about this too.

I think this is a picture of the the 748RS system (note: NOT 100% SURE): http://www.ducatisportingclub.com/xmb/viewthread.php?action=attachment&tid=17933&pid=161837

Lastly, here's a link to someone who installed corse breather tank, corse airbox breather, and corse crankcase breather. Note on picture 16 is the corse airbox breather installed in the airbox (It's to the left of the red bracket). http://public.fotki.com/garymilcheck/motorcycles/748r/corse_cb_install/

Hope this helps.
 

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Thanks for the reply, yes I read the same post but there is conflicting information in it under the 'Here’s what the experts say' title;

With BCM Ducati saying;

"The simplest solution is to hollow out the reed assembly and leave it internally open but still hitched to the volume bottle. This allows the volume of the breather bottle to perform its function and usually gives a slight horsepower increase also.

Then, use either a 748RS reed valve in the airbox at the end of the breather hose, OR, use a Ford diverter valve (in-line one way) just before the airbox."

And Jon Nichols saying;

"We firmly believe the best system is the stock system."

So I'm confused here, I'm not going to get the Corsa breather box but I need to do something because my breather is a mess, so either I get a new breather (poss Nichols?) or I alter the setup, if it is an improvement over the stock setup, as per BCM reccomendations?, or I just vent it to the atmosphere and be responsible for a bit more global warming - we could do with a warmer climate in England anyway ;)

:)
 

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DukeDesmo,

I re-read the post again, looks like Jon Nichols is recommending that the stock system be kept and only change the crankcase breather if it is leaking.

The BCM solution is to use a hollow crankcase breather, connected to the stock volume bottle, and then connect the volume bottle to the airbox with the corse airbox breather. The corse underseat breather box is not used.

This solution looks to be what Section8Superbike is recommending also. Here is Section8Superbike's description:

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Corse Airbox Breather Valve. We use these in conjunction with the DP Aluminum Crankcase Breathers # 966019AAA to create a "cheater" race breather system. You will be putting this valve inside the airbox and removing the reed valves from the DP unit. There is a little grinding and so on involved in getting the airbox valve to install just right, but it's worth it. This system will eliminate almost all oil pumping issues your bike may be suffering. This is a very similar setup to the one run by the Briel World Supersport 749R team. We put this setup on all of our racebikes.
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I find this interesting because the post from Motowheels says that removing the reed valve from the crankcase breather will overwhelm the stock OEM breather box.

Has anyone installed a breather like the way BCM or Section8Superbike recommends?
 

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Discussion Starter #16 (Edited)
quote from dukedesmo,
Yes, I've seen that on their website and it looks good, I am considering that as a direct replacement, but I was wondering if there's any merit in fitting the one-way valve further away from the crankcase, either just before or in the Airbox as per 748RS? or an in-line diverter valve as described on the link from the archive?





that is precisely what the krankvent is supposed to do, the problem with most breathers is they wear out reasonably quickly and cannot maintain a seal. once the downward stroke on each piston has been completed, the krankvent is supposed to seal the crankcase from sucking air back in, thus maintaining the negative crankcase pressure generated by expelling excess air on the downward stroke of the pistons. if there is more pressure generated by combustion gases passing the rings, the krankvent is supposed to expel these while maintaining the negative pressure. krankvent also state that the negative pressure helps with ring seal as flutter is eliminated.
sod it! i'm buying one. i'll let you know how it works when it's installed.
cheers,
paul.
 

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Shoie said:
I find this interesting because the post from Motowheels says that removing the reed valve from the crankcase breather will overwhelm the stock OEM breather box.
Indeed, either it does or it doesn't - the more I learn the less I know....... :)
 

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loony888 said:
that is precisely what the krankvent is supposed to do, the problem with most breathers is they wear out reasonably quickly and cannot maintain a seal. once the downward stroke on each piston has been completed, the krankvent is supposed to seal the crankcase from sucking air back in, thus maintaining the negative crankcase pressure generated by expelling excess air on the downward stroke of the pistons. if there is more pressure generated by combustion gases passing the rings, the krankvent is supposed to expel these while maintaining the negative pressure. krankvent also state that the negative pressure helps with ring seal as flutter is eliminated.
sod it! i'm buying one. i'll let you know how it works when it's installed.
cheers,
paul.
Isn't that what the OEM or Nichols valve does? or does it do it differently?
 

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Discussion Starter #19
that's what the std one does, yes. but the desmoquattro supposedly has a crankcase ventilation issue when modified. the early race motors had two breathers to solve the problem. granted, i'm not riding a race bike, but i'm not keen on positive pressure possibly blowing gaskets and seals, so before i modify it i want a solution. the main problem seems to be the longevity of the std item, therefore, i want a reliable, permanent alternative to what is available as std. without paying for corse bits!
 
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