crank case breather question - Ducati.ms

kt57 · Apr 29th, 2006, 10:26 pm

I have a nichols crank case breather and thought of putting a K&N filter on it and removing the stock set up. I read on another thread that it could negatively affect performance. Is this true? It does not seem that there could be much of an affect on crank case pressure.

sk66 · Apr 29th, 2006, 10:45 pm

negatively affect performance?! I doubt it! IME it works better than the stock system, AND theoreticly it should...

xseal · Apr 30th, 2006, 6:52 am

the conventional wisdom is that you need a breather box, the larger capacity the better. The K&N solution is a bad idea b/c if you build up high pressure, you will mist/lead oil at a very bad place to do it, ie, in front of the rear wheel. All race bikes use a breather box, perhaps the K&N is acceptable for street use.

NCRick · Apr 30th, 2006, 7:27 am

There is really no problem with the stock system using the new breather anyhow.

JDuc · May 2nd, 2006, 2:49 pm

I have heard the same things about the K&N breather mod.

Something about venting the crank to where it can spray oil on my rear tire just doesn't settle well with me....and I can't imagine it helping performance that much to where it would be worth risking it....but that's just me

fraz · May 2nd, 2006, 7:46 pm

I already had the K&N filter conversion when I bought the bike and the stock airbox is all cut up so going back isn't an option. If anything, I will make a catch can and may do so anyways. I heard stories about the leaky stock breather and decided to go Nichols. I just installed it and rode it yesterday for the first time for quite a few miles. The old stock leaky POS was plastic and dumped tons of oil over the back of the motor. So far, the Nichols breather and everything around it is still oil free. Planning on riding a bit this weekend so I will post back here as to my results. Typically the things to push oil out is romping on it at low speed and doing wheelies. When riding mellow it leaked very little if at all.

BTW, it is even more of a concern for me because I don't have a rear fender. That way the oil goes directly on the tire

Let's knock on wood that this fixes the problem.

NCRick · May 2nd, 2006, 11:32 pm

you could rout it into the stock canister under the seat and then into a catch can or up near the air box. The stock canister is designed to coalless (sp) the oil vapor into a liquid and alow it to run back into the crankcase, minimizing what goes to the air box. Very little seems to make it into mine. my stock breather works with only a little oil you can see because of the dirt that collects by it. it takes several hundred miles to see any at all.

IronBeard · May 27th, 2009, 9:05 am

I'm in same situation - bought my 02 900ss and it had a K&N crankcase breather installed already. It's an oily mess around the filter. I just ordered a Nichols. Hoping that this will solve my problem.

Lucille8 · May 27th, 2009, 10:11 am

I have a STM breather, and used a K&N filter for years. However, it would put a light mist of oil on the swingarm. I put the stock airbox for the breather back on, and bought clear/reinforced tubbing from Home Depot. I like the looks better, and no misting problems.

Pacman · Jun 4th, 2009, 10:05 am

I have a gutted stock breather with a long hose up under the rear of the seat. No pressure build up in the crankcase, and too long to overflow even on hot summer track days. Works like a charm...