[dj]

Has anyone installed on of these on their Duc? I'm planning de-smogging my bike next weekend, installing a small K&N breather filter. But I came across this today and am wondering about it. Pros, Cons, etc..

http://www.nicholsmfg.com/breather.html

 

[MagnusVer]

I did... de-smogged, nichols breather, k&n breather filter. It looks alot nicer without all that extra crap... emissions canister, crankcase breather vent box, cables, etc. The danger is oil blow by out of the filter.. I experienced a little of this initially, but I believe it was filter oil, not crankcase oil.

Some say you lose power with these mods... I didn't really notice any difference. Some install the nichols breather but no k&n. For me it was worth it just to get all that extraneous garbage out of there and clean up the look of the bike. The debate lingers on....

 

[test-reg]

go with the Nichols breather if you want. personally, i would keep the breather box. it does help relieve crankcase pressure, which is a good thing.

 

[test-reg]

o yeah. you will loose power without the breather box, but it would be insignificant. no power loss or gain by eliminating the evaporative canister.

 

[MNMONSTER750]

Why would you loose power without the breather box??

 

[test-reg]

Without the breather box you will have excessive crankcase pressure.

 

[CuStOm]

If you stock breather is not leaking, then don't bother replacing it unless you want the bling. The newer style factory breathers do not leak like the older ones.
Do not run an open K&N on there, it is not as efficient as the stock system and does indeed introduce a safety issue.
http://ducatisportingclub.com/control/boards/viewthread.php?tid=3053
I also have a link saved at home where Bruce from BCM did some testing and found that the open element reduced horsepower every time. Had to do with a volume displacement curve that once you exceeded the maximum efficient volume then you lost horsepower. Hence open air being infinite.

 

[test-reg]

Where does the crankcase pressure come from? Ring blowby?

How much pressure can really build up? I've never heard of a huge issue with it unless your rings are totally shot.

There is some blowby in all engines no matter how perfect they are. On big V twins, or ant two cylinder engines the pressure increases due to piston size.

 

[test-reg]

If this is the case, then what does everyone install when they remove the stock emissions equipment???

What most of us remove is the evaporative canister, the juice can by the wishbone on older monsters and the plastic box on the newer ones. Pod air filters require the removal of the breather box. If the breather box is removed a K&N or similar filter is used and the price paid is higher crankcase pressure since you do not have the negative pressure in the airbox to help scavenge. The effect is not very significant so the choice becomes yours. If you go that route I suggest mounting the filter high as there is a (slim) chance you could oil your back tire.

 

[Guest]

Thing is you have to remember that the airbox and crankcase box are both undersized compared to sbks so a K&N filter won't have the same effect on hp.

 

[Fillmore]

Actually, a smaller crankcase with similar sized pistons would create more crankcase pressure... a smaller airbox would also have more effect. (pushing same amount of air into a smaller space creates more pressure, drawing same amount of air out of a smaller space creates more vacuum)

I tend to remove the hoses and breather boxes and replace with a K&N on my bikes, but I realize that I'm sacrificing a little bit of HP for looks and ease of maintenance.

My experience is that the Nichols breather valve does two things... It eliminates the oil leak that older bikes would experience around the base of the stock breather, it seems to control blow-by a bit better than the stock breather valve. I've also experienced that some other aftermarket breather valves allow more blow-by than the stock breather and some actually honk/sigh when the bike is shut off...

As noted above, because of the blow-by issue, if you choose to run the K&N it's probably safer if you run a section of hose and mount the filter a bit above the breather valve, instead of mounting the filter directly to the valve. This way a majority of blow-by oil just go into the hose and eventually back into the case instead of saturating the filter and eventually leaking on the back of the bike. I haven't seen this problem on my Nichols equipped bikes (I do have the filter mounted directly to the Nichols breather valve on my 888), but it's been an issue with some other aftermarket breathers (STM being one that I remember).

--Fillmore