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The breather valve controls the in and out in an Evo engine, Wes.
I have noticed this valve in the parts schematics but have not actually seen it in the flesh. I have never torn apart a V-twin engine. I did not know that this valve was associated with the in and out of the crankcase air volume.
I will now go and see if I can determine how this valve vents to the atmosphere to let the crankcase breathe.
If nothing else, I can present you gentlemen with some merriment as I try to figure out this engine's workings.
Or, just run longer 12 tubing to pipe out down and out behind motor to dump oil to ground.
On oil changes every 5K, have about a inch of oil that is absorbed by the foam in the catch can, and easy to empty it out since allen socket on bottom of catch can to spin the bottom of can off.
I took the vent line from the breather tube on the S&S intake on my twin cam and ran it to a catch can and then just let the can vent under the bike, pretty much nothing made it past the can. Every oil change I would dump the can, I was surprised to see that about 85 or 90% of the contents was water. This can had a little dipstick on it so you could check anytime.
Yes, with the catch can not being able to heat up enough to boil the steam/petrol out of the mix to just trap the oil alone, end up with a lot of other than oil in the catch can to fill it up faster.
So where I have catch can, does get heat from the motor to boil the water/vaporize petrol out of what is collected in the catch can, and what is left behind for the most part, is the oil that is absorbed in the foam alone.
Hose to the ground on a Harley is how God intended it's design, if that doesn't work you have too much ring blow by and needs rings. Where in the hell is John the TC terminator, I've seen pics of 3 different Twin Cam engines in the Classic Evo used as references for how to guidelines, someone check on him.
Hose to the ground on a Harley is how God intended it's design, if that doesn't work you have too much ring blow by and needs rings. Where in the hell is John the TC terminator, I've seen pics of 3 different Twin Cam engines in the Classic Evo used as references for how to guidelines, someone check on him.
That was the problem that I was having. The external breather bypass is mostly illustrated on engines other than Evo.
Another thing that I noticed is the volume of air caused by the piston displacement. There are lots of places that state that the air is vented (inhale, exhale) but do not give the particulars. An example is the link that I provided in a post above.
On the downstroke (exhale), I can see 80 cu in of air leaving the crankcase through the breather tube. (That's a lot of volume!) But in the upstroke (inhale), I do not see where the air rushes into the crankcase.
That was the problem that I was having. The external breather bypass is mostly illustrated on engines other than Evo.
Another thing that I noticed is the volume of air caused by the piston displacement. There are lots of places that state that the air is vented (inhale, exhale) but do not give the particulars. An example is the link that I provided in a post above.
On the downstroke (exhale), I can see 80 cu in of air leaving the crankcase through the breather tube. (That's a lot of volume!) But in the upstroke (inhale), I do not see where the air rushes into the crankcase.
Again...I would love to See...record, prove, anything But Pressure (out) on any Shovel or Evo Crankcase!!
Theory and Conjecture is Nice...But never Won a Race!! Nor fixed a problem that did Not exist!!
Last edited by Racepres; Sep 15, 2024 at 08:32 AM.
Again...I would love to See...record, prove, anything But Pressure (out) on any Shovel or Evo Crankcase!!
Theory and Conjecture is Nice...But never Won a Race!! Nor fixed a problem that did Not exist!!
That is what I am seeing. Pressure out. And the geared breather valve controlling the direction of the air oil-mist flow circulation within the crankcase for lubrication. This sort of tells me that I do not want to have my bike idle for long periods of time without revving the engine a bit.
On the downstroke (exhale), I can see 80 cu in of air leaving the crankcase through the breather tube. (That's a lot of volume!)
You are confused on the function of the breather setup on a harley engine. It relieves excess crankcase pressure to atmosphere. Not related to intake of 80 cubes of air at all..
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