I have a '91 FXR stock EVO. I am getting A LOT of oil blowing back from crankcase to the air cleaner element through the crankcase ventilation hose. I assume this is due to a common problem called "sumping" whereby a check valve does not function properly and allows oil to drain down from the oil tank and fill the crankcase when the bike is sitting for a long time (as in over the winter). There is some sort of canister element installed inline on the vent hose between the breather and the crankcase. It looks like it might be an aftermarket regulator to prevent that from happening? At first I thought it was some sort of PCV valve like on a car, but there are no moving parts, just two canister halves, inside is what looks like a diverter with five holes in it, so the oil has to

Do I just live with it or can it be corrected?

Steve D.
Minden NV

 

some guys just reroute the hose avoiding the aircleaner.There are also filters you can purchase.There are also complete kits with new chrome lines and a filter.I had that problem with my old 92 Ultra.take a look at these on Ebay: 130390726306 or, 320418908915
Hope this helps, just do a search for harley parts,crankcase vent.

 

There were a lot of "fixes" for the EVO air cleaner problem with oil. A lot of guys just ran a fliter off of the breather hose driectly from the oil pump down under the scooter mounted in an "out of the way place" . I did this on my 92 FLHTCU and never had any further problems. Some will say this was not the way to go. Oh well. There is a lot of print on this topic out in cyberland. Here is a link to a company that makes a breather filter and "catch canister" for them. http://www.cas4.com/engine/engine-cr...r-valves2.html Maybe this will help you. Also there is a "fix" to the oil bleeding into the crankcase after sitting for a long period of time. Stop by the HD shop and get a new check ball and spring ( some guys get two check ***** ... they take one and use a hammer and drift and give the check ball a "love tap" to reshape the seat then remove the ball and place the new one along with the new spring ) . This is a quick and easy repair. Hope this helps!

 

your breather inside your engine, driven by your cam shaft might also need replacing. A lot of them are plastic & when they wear down or get scratched, they can let some oil through. Easy job to replace! Best bet though is re route your breather line & add a breather filter to the end. Their less than $10.
Hatch.

 

You had better assume this is due to worn piston rings. The "cannister" is supposed to separate the oil from the air before it goes into the air cleaner. Removing it will make the problem worse.

 

This subject has been covered before, but how feasible would it be to put a manual valve in the line to prevent sumping? I know, don't forget to open the valve when you ride. Thoughts?

 

I found out that the cannister I referred to in my original post is a Hayden "Krank Vent Plus" which is supposed to relieve pressure in the crankcase. It was on the bike when I bought it.

 

Just did a search on Hayden, 2 to 8% increase in hp? Really? For $125 bucks? Seems like not such a bad deal for no oil on the floor and more power. jmho.

 

Most bikes will sump if their left to sit but once started, the oil returns to the bag quickly! There is still oil blasting around in the case when the bike is running which is why the plastic breather is inside. It is timed with the cam shaft to open & close through the different strokes to help relieve crank case pressures.
Hatch.

 

Hatchetman is correct about the breather gear in the timing case. Also something to consider is correcting the opening in the cavity that the breather gear "breathes" through. It is a very rough opening. S&S strongly suggests that you reshape ( read open the window to the proper dimensions ) the opening whenever you go into the timing case for any necessary repairs or maintanance. This helped immensely on mine.