Looking for input.... : V-Twin Forum: Harley Davidson Forums

Tech23 · 10-31-2009, 11:54 PM

Looking for input,

Anyone running one of these crankcase breathers......

http://www.kuryakyn.com/index.cfm/go.../109/IMID/1046

It looks like it would end the drip I get out of the air cleaner onto the cam over. In the installation instructions it states the prefered way to vent this breather is with an open tube under the tank facing rearwards toward the seat. On my 2000 Dyna there is a plastic harness guide channel that sits on the frame backbone, that the vent tube could neatly be inserted into, to hide the vent hose. I'm wondering if this will eventually start to drip oil on the rear rocker cover.

Tech23

Tech23 · 11-11-2009, 12:38 AM

OK, I guess no one is using the Kuryakyn breather. I have the early style free breathing intake with the external breather pipe. Has anyone with this style intake modified the breather on their twin cam to keep the air filter from dripping oil? I have several ideas in mind, I just want to see what others have done and how well it's working. On this setup the breather hose enters the air cleaner backing plate below the carb throat. When the engine is shut down oil drips from the breather hose on to the air filter. The new style HD free breathing intake (Ness style) has the breather passages incorporated into the air cleaner backing plate with rubber hoses that aim the crankcase vent much closer to the carb/throttle body throat so the oil mist is better able to be sucked right into the intake. Does this setup cure the drip from the air filter when the engine is shut off? Has any one with this new style setup modified the breather?

Any crankase vent run downward would likely drip or need a filter, or collector. There are several on the market to do this. Any crankcase vent run up under the tank as high as possible then down the frame backbone toward the seat would probably return the oil to the engine, eliminating any drip because the oil wont be able to push that high. That's why I was asking about the Kuryakyn breather. In the installation instructions on thier site the preferred vent arrangement with this breather is up under the tank and toward the seat along the frame backbone with no filter. Open hose to atmosphere.

Tech23

46u · 11-21-2009, 02:33 PM

Just curious what year and model bike do you have.

arealinvestor · 11-21-2009, 02:50 PM

They don't make one for late model HD's 09-10???

plongson · 11-21-2009, 03:03 PM

Follow this thread...
http://www.v-twinforum.com/forums/tw...er-ground.html

Tech23 · 11-23-2009, 04:12 AM

Quote:

Originally Posted by plongson

Follow this thread...
http://www.v-twinforum.com/forums/tw...er-ground.html

Thank you,

Read the thread, and have talked with some people, and these question's remain.

If vented upward, will the oil percolate in the hose and eventually come out anyway?

Is it posssible that oil trapped in the hose will block the crankcase from venting properly?

Will oil actually drain back or will it just sit there and accumulate in the breather port....several people have stated that once oil has made it past the umbrella valves and into the breather port it is on a one way journey and must exit. There seems to be some debate on this point....is this fact or fiction?

Tech23

wkohn · 11-23-2009, 04:33 AM

Quote:

Originally Posted by Tech23

Looking for input,

Anyone running one of these crankcase breathers......

http://www.kuryakyn.com/index.cfm/go.../109/IMID/1046

It looks like it would end the drip I get out of the air cleaner onto the cam over. In the installation instructions it states the prefered way to vent this breather is with an open tube under the tank facing rearwards toward the seat. On my 2000 Dyna there is a plastic harness guide channel that sits on the frame backbone, that the vent tube could neatly be inserted into, to hide the vent hose. I'm wondering if this will eventually start to drip oil on the rear rocker cover.

Tech23

I think for it to really work you would need the hose fitting to be on the bottom instead of the top. Oil does not drain up but does drain down.

plongson · 11-23-2009, 07:05 AM

It wont drain back. I just installed this vent system on my FLHRCI and if you blow on the hose NO air passes. If you suck on the hose, you get air. It seems to me it could be a easy troubleshooting tool to check the operation of the umbrella valves...

Any oil trapped in an upward hose will just accumulate, not drain back.

gsxrboy96 · 11-23-2009, 07:57 AM

Quote:

Originally Posted by Tech23

Thank you,

Read the thread, and have talked with some people, and these question's remain.

If vented upward, will the oil percolate in the hose and eventually come out anyway?

Is it posssible that oil trapped in the hose will block the crankcase from venting properly?

Will oil actually drain back or will it just sit there and accumulate in the breather port....several people have stated that once oil has made it past the umbrella valves and into the breather port it is on a one way journey and must exit. There seems to be some debate on this point....is this fact or fiction?

Tech23

Tech, for what its worth, on my s and s motor on my titan, i vented the crankcase with a tube and a k and n breather up by the neck of the bike. so it was vented up and it was clean, but then i constantly worried about the oil being trapped in the tube as it was traveling up and cutting off crankcase ventalation, the really only remedy to this problem is to use a arlen ness type back plate where it pulls the oil in for consumption.

p.s I know im prolly going to catch heat for this, but reguardless of what every ole harley mechanic says, i see no way for this to hinder performance at all, if anything a positive crankcase vetaliation would and could possibly add hp, thats why you see every race car in the country running a crankcase hose to a header which promotes scaveging or some even more exotic set ups run a pump. And if your worried about that small amount of oil being burnt, consider this, on every cirlce track motor ive built, they get no valve seals, and the motors are strong. hope that helps.

plongson · 11-23-2009, 01:21 PM

My biggest concern was the build-up and accumulation of carbon on the heads and pistons. Bad JuJu...hot spots, heat soak, propensity to ping, reduced fuel mileage etc.etc. Nothing good about carbon.

Tech23 · 11-25-2009, 12:53 AM

Hey, thanks for all the replys. There are many different versions of breather setups. The majority seem to agree that using the factory head breather ports, it's best to run the hoses downward so that oil mist can escape without creating a poor or non functioning breather system.

I thought I would post a pic of another riders setup here. He blocks the stock breather ports, and moves the breather hose nipple to the highest part on the rocker box cover. It appears this would drain back with no trapped oil, or accumulation, although he has stated that he still will get a drop or two out the end of the hose which is routed up, then along the backbone of the frame and down toward the ground.

Tech23