crank case breather tube blowing oil

[ironman2]

 This issue has been a ugly pain for me for too long! I have an 1981 shovelhead. bikes in great shape.Although occasionally i get a lot of oil spitting out from crankcase tube and i mean a big puddle.Its not after the bike been sitting all winter and then start it. It will happen during riding season.And not just initial start up, I can take a ride, shut bike down,restart it any where from 60 seconds to 30 minutes and the oil comes out ccvtube . And this does not happen every time I go for a ride it might happen 3 times a day or 3 times in 30 rides??       Its had some motor work from a reputable motorcycle shop in cny.the motor is a 93" s+s sidewinder kit.With decked heads, linewebber cam,external oil  lines that return from heads  into the back of motor behind oil pump , original cases, I've brought the issue back to shop that did motor work And they have not  resolved issue although they tried W/ s+s reed type breather, larger breather gear.  I've changed spring and check valve ball in oil pump. Yes this is long winded just trying to give as much info as possible. Any suggestions appreciated.

[blisterbut]

have you checked the breather timing ?

[ironman2]

yes ,I've had the cam cover of and the marks all align.

[shovelbill]

check the ball, sounds like oil sumping in the case

[monty101]

I'm betting that the inch long plastic spiral oil separator that slides into the breather tube that sticks into the cases and is mounted inside the lower rear of the cam cover is missing. Old panheads actually had a screen to bust up the oil so the mist was all that got blown out the breather line. Shovelhead went to the plastic oil separator that looks kinda like a "spiral staircase" to bust up the oil...

[tbkickstart2]

Did this just start doing this after you put the stroker kit in it? Do you have the right cam cover and gasket on it?

[ironman2]

yes ,when I bought the bike it had a 88" motor then I went to a 93" the oil puking out of crank case breather tube started after the 93" kit was installed. As far as I know it's the correct cam cover and gasket looks exactly like old one? Although the cam cover was changed when the 93" went in?  Thanks

[monty101]

Well if didn't puke oil before then it almost has to be the oil separator dropped out of the cam cover tube and nothing stops the oil from dumping out the breather line.

[Lew]

I'd be having a look for proper vent line routing.  Making sure the tank vent and oil return lines are in the right place.  Check for restricted return oil to and from a filter and/or cooler and the tank.  Might test to determine a possible compression leak into the case.  If nothing is found...I'd pull the oil pump apart and have a look for sheared key/s.  Good luck!

Lew

[75fxe]

Does anyone havge a part number for the spiral plastic oil separator?  I've never seen one and I couldn't find it in my parts book.

[monty101]

http://www.retrocycle.com/CustomChromeParts/14524/Cam_Cover_AirOil_Separators.html#top

AIR/OIL SEPERATORS 10 PK OEM# 25329-91

[monty101]

After I got my 96 incher running, It would blow oil out the breather line every time I started it up and after it blew the small amt of oil out of the cases it would stop blowing the oil. I remembered that my old panhead had a wire screen inside the cases in the cavity that separated the cam cover mounted breather tube from the cavity side that was hooked up to the breather hose and I checked into it and decided that the screen's purpose was to screen out the oil from the oil mist on start up until the oil pump caught up and cleared the lower end of oil. There's really not much oil in the lower end at start up unless you have a leaking check valve but a small amt of oil on the return may also leak back past the oil ring mounted in the oil pump that the oil pump shaft runs in. To make a long story short my oil pump o-ring was bad and a small amt of oil did seep back. I went to a local shop and they told me that the panhead motor did have the screen and I could put one in the shovelhead but the plastic oil separator was what was used by harley now and replaced the screen. I put one in and no more start up breather line oil problems. later on I replaced the o-ring that fit in the oil pump that the oil pump shaft ran in. Hope this helps. If you have a leaking check valve , take the check valve ball out, get a old push rod and put some valve grinding compound on it and stick it in the oil pump fixture that the check valve ball is seated in and spin it a few time and reseat the check valve. That should stop all oil bleed by except a bad o-ring and since mine had a bad o-ring and the separator fixed that problem you should be ok even if the o-ring is bad. It won't leak a lot back but mind had a oil filter and cooler mounted on the front leg and that meant I had more bleed back from the hoses that went to the cooler than most motors would have. Hope this helps you. The harley hose and most shops carry the plastic separator and its pretty cheap.