True. Breather bypass is sort of an OCD thing and I'll be the first to admit it; just put a catch can on my new truck and it already caught about a tablespoon of oil after 100 miles....probably a good part of it is condensation. But you'd actually be pulling LESS vacuum at those RPM's you're running.
You're right on the vacuum. I always over think that.
I believe the breather re-route on a twin cylinder engine is more important that on an engine with more cylinders.
This was my way of doing the AN breather by pass. Something to do, cheap and easy, i enjoyed it and it has eliminated oil going into my breather and the drippage i was getting off the filter cover. On long rides, even with the oil level where is was supposed to be, i was getting oil into the back of my filter cover and even some drips after awhile.
This was my way of doing the AN breather by pass. Something to do, cheap and easy, i enjoyed it and it has eliminated oil going into my breather and the drippage i was getting off the filter cover. On long rides, even with the oil level where is was supposed to be, i was getting oil into the back of my filter cover and even some drips after awhile.
I really don't know why some guys are putting a filter on the breather. Vapor is expelled through there and cannot go the other way due to the umbrella valves in the rocker box; air cannot go up that tube. All the filter will do is catch the oil until it gets saturated enough and then it'll start dripping too. Also, it restricts the flow of the crankcase vapors and since vacuum from the intake is no longer pulling the vapors out, it passively vents so you really don't want any restriction at all.....unless I'm completely missing something. I just ran my breather tube down behind the transmission with no filter and it dumps to the ground.
I did the by pass with a filter on the end of the hose and later removed it. It's been over 6 months and over four thousand miles later. I have nothing dripping down on the floor from the hose yet so I'm leaving it off. If it starts leaking on the floor, I'll put it back on.
I took a round, flexible piece of pipe from the plumbing aisle and bent it to match the angles on the bike. I then hammered it into a rectangle. Primed it, and painted it a cheap metallic silver, which matches the motor well. 3/8" tubing out of the breather bolts, into a T just under air cleaner and connected it to the metal tube. Out of the metal tube, 3/8" rubber tubing and zip tied to the frame.
I'd be willing to be it doesn't get hardly any oil in the filter at all. Once you divert it and the vacuum effect of the throttle body isn't pulling on it, you hardly get anything out of it at all.
There's still quite a bit of goo that comes out of those hoses, even without the vacuum of the intake. Just ask the catch can guys. I had a catch can on my previous bike and I could drain several spoon fulls of fluid after every ride.
It doesn't matter whether you run the oil level low or not you still get oil residue sucked into your intake which turns into carbon build up on top of the piston. Just because you don't get the oil slobber doesn't mean this isn't a good idea to route it to the ground. The new Rushmore breather tubes make this easier than ever. Use the stock breather bolts, or for the thicker backplates the Kuryakyn breather tubes that are 1-3/4"(9976) long will work. Using the Rushmore breather tubes makes it easy to add extra hose and route it any which way you want it to go.
Do you have the part # for the Kuryakyn breather bolts and where did you get them? Does one have to use the Rushmore breather tubes or can one just use the Kuryakyn breather bolts with the big sucker? I have a big sucker on my 2009 dyna and am interested in this mod. Thanks for your help.
02-24-2017, 02:11 PM
