Oil carry-over from the breathers on my Evo

Ever since I rebuilt my Evo, when I run at high rpms, I get oil carry-over from the breathers, and it drips into the S&S air cleaner and spatters out on my rear pipe. Not a lot, but enough to show oil smears on the oil tank and pipe.
This is a common Evo problem, one that the Moco didn't care to fix over the years.


This is totally unacceptable!

I located a "fix" called "Cure Vent Plus", basically, it's a couple of vent extensions that you install in the breather bores in the heads, and they have a ball and seat that acts like a check valve to keep the oil from coming out of the breathers. I'm waiting for it to show up, when I get it I will do a show & tell for you other Evo guys. I also will be installing a replacement for the stock rotating crankcase breather, the S & S breather is a set of reed valves that operate based on crankcase pressure.

[pa-glazier]

Do they have one for the twin cam?

[HDMD 88]

Originally Posted by Woody218

Ever since I rebuilt my Evo, when I run at high rpms, I get oil carry-over from the breathers, and it drips into the S&S air cleaner and spatters out on my rear pipe. Not a lot, but enough to show oil smears on the oil tank and pipe.
This is a common Evo problem, one that the Moco didn't care to fix over the years.


This is totally unacceptable!

I located a "fix" called "Cure Vent Plus", basically, it's a couple of vent extensions that you install in the breather bores in the heads, and they have a ball and seat that acts like a check valve to keep the oil from coming out of the breathers. I'm waiting for it to show up, when I get it I will do a show & tell for you other Evo guys. I also will be installing a replacement for the stock rotating crankcase breather, the S & S breather is a set of reed valves that operate based on crankcase pressure.

Woody
I have used a kit called ''Nose Bleed Cure" which was a small extension tube and 2 drill bits. With the 1/2'' drill bit you would drill out the oil port hole in the rocker box next to the umbrella valve and press in this extension tube, the small 1/8'' bit would be used to drill the oil return hole larger next to the umbrella valve. I have found if you relieve the top rocker box a little to unshroud the air flow from the extension getting too close the the top box the breather would work better. The kit worked wonders...I never had one that didn't stop the oil carry over, but at high speeds for a prolonged period of time I still seen some signs of oil specks on the customers bike. The best way I found to get rid of all the spots was to install a ''LIGHT DAY'S PADS'' from your wife's (or girl friend) secret stash, these pads installed in the bottom of your air filter cover will absorb ALL the oil and not let a drop leave the air filter. One thing you have to remember....they won't last forever so they must be changed every 28 days....

You might want to think about the S&S breather....it's always nice to get rid of something that moves inside a motor but the reed valve does not give you the efficient oiling of the cam, lifters, and cam gears as the stock rotating breather. These items all get their oil from the collection of oil from the flywheels off the oil scrapers and stored in the rotating breather until the pistons come down and the breather opens up to the cam chest and that stored oil is then expelled into the cam chest under crank case pressure caused by the piston down stroke. The Reed Valve can't hold all that oil plus there is only one reed valve out of three facing the cam chest. Not all trick items are so tricky believe me. If you want an improvement over the stock plastic breather buy a metal one just like it....the metal one won't eat into the breather bore like the plastic one does.
Doc

[Type O]

run the breather out the bottem of the bike it worked for me . do yoou have breather heads or none breather heads ? turn the breather 90 degrees and run a hose frome and tie strap it to the bike