Bottom breather using head breather rockers

Discussion in 'General Harley Davidson Topic' started by FFF88, May 28, 2014.

  1. FFF88

    FFF88 New Member

    Hey guys, new to the forum and hoping some of you "who have seen it all" so to speak can offer your real world experience. This is going to be long so i apologize up front. :) i have a 1990 Ultra that has 1992 breather type rocker boxes on it. The front just doesnt like to stay sealed. (at dring and top, not base to cylinder. rear is fine. had them on marble, not warped. 3 sets of rubber gaskets, always leaks. tried copper spry, etc. i am finally going back to cork gaskets tonight.( pre 92 gaskets) i have pulled cam chest, checked breather gear and timing, oil lines free flowing, etc. i vent to atmosphere with a little filter on end under bike. free and clear flowing. my motor came back from MOCO couple years ago freshly rebuilt with 1992 breather type rockers on it (not sure why, previous owner claims) since my motor does not breathe out the top, should i just pull the umbrella valve out of the intake side? or add one to the exhaust side runninig both? oil must be pooling up in the box and then pressure pushing it out the weak link gasket. so all that and my real question is, since i need to keep these boxes for now due to funds, should i ditch the umbrella on intake side (only one in), add the other umbrella, drill out the holes larger to 1/8th to allow easier oil return, what can i do that i havent checked/done already? i thought it was excess pressure but now not soo sure since all seems to be working correctly. just frustrated.... Thanks
  2. Breeze3at

    Breeze3at Well-Known Member

    I have a late model '92 that came with empty head breather rocker boxes and 1/2" tapped heads,but breathes thru the crank case. I think just using solid bolts to the heads/air filter mount would negate the dual breathing.
  3. fin_676

    fin_676 Experienced Member Staff Member Moderator Contributor

    My 92 softail also has the head breather heads and a bottom breather the head breathers are blocked with solid bolts so the bottom breather is the working one
    Bike was very low miles when I got it 7 years back and I have had no issues with it so I have not had the heads off it yet

  4. FFF88

    FFF88 New Member

    Thanks for the replies! Mine is just a bottom breather with solid bolts. my heads are not breather heads. just the later style boxes and the front keeps leaking so i'm wondering if anyone uses the newer boxes on the older heads and if they use umbrella valves or not. or if it even makes a difference. it seems oil is not draining back down fast enough from the boxes and filling up the front and forcing it with force out the box. any ideas for me to check other than what i posted already? Thanks