Crankcase breather

I replaced my crankcase vent system with the Evelozione breather filter. Stoppped by my local dealer and they told me there would not be enough backpressure with that setup and I needed to run a long hose and put the filter on the end of that.

Huuh

You guys running a filter right off the seperator at the crankcase with any problems?

Scott

Do a search. There is tons of information on the subject. The general consensus is to leave it stock but replace the breather with an aftermarket one if it leaks. But if you must put the k & n filter thingy on, then use the stock tube that goes from the breather to the box (or one about that length), remove the box and hose that goes to the airbox. Place the filter at the end of the hose from the breather, zip ty the filter in the spot the box was under the seat.

Ok I did not like the looks of the stock tube running up under the seat with the crankcase filter attached.

Since my first post I confirmed here and with a friend who builds Duc motors that crankcase pressure is critical to keeping from oil starving the motor.

So I took a 1/2" id piece of gray PVC and cut a length to fit all the way up into the Evoluzione breather filter. Then hacked off enough so the filter would fit over the crankase reed valve and push the PVC to the inside top of the filter.

I removed the PVC and drilled three 1/16 holes through it all around, slipped it back in and tested it for good airflow.

I slipped it back up inside the filter added a rubber O ring for a good seal and slipped it on and put a hose clamp on it.

Now it has free, filtered breathing but restricted down substantially giving good back pressure.

Scott

Hey mouser, sorry to sound ignorant, but I am currently redoing my stock setup, too. Can you redescribe this mod in greater detail? Maybe w/ pics? I'd really appreciate the help...you can contact me directly at sinikal1.at.cox.net. Thanks...

I'm running both of my Ducs with STM breather valves with K&N filters. The Monster has had this combo for the last year and a half (about 3k miles) with no problems. I just did the SS this last January and have ridden it about 1k miles with no problems. The reason I changed the breather valves is that the older ones tend to weep oil all over the rear of the engine and both of mine were doing just that. The oil comes from where the plastic top of the breather meets with the aluminum casing. Very messy. I also did not add an extention tube for the filters. Nor did I oil them.

I'm not sure how much of a factor crankcase pressure plays in oiling of the engine since the oil pump is capable of 20+ psi at idle in a hot engine and 60+ psi at 3.5k - 4k in a hot engine but crankcase pressure is maintained by the breather valve and not the tube attached to it. Check out the inside of an STM or Nichols breather valve sometime. You'll see what I mean; little one-way flutter valves. Hope this helps.