1. After 20+ years it's time to pass the torch. If you are interested in acquiring this forum please contact support@cv-performance.com for details. Any spam will be reported and blocked.
  2. Welcome to Bike Talk, a forum for all bikers and motorcycle enthusiasts. If you are new to Bike Talk, be sure to register for free and join the conversation.

    There's always someone around willing to help out with questions or give a friendly wave back. All Harley and metric riders are welcome.

Crankcase breather hose

Discussion in 'Motorcycle Tech Talk' started by riddlej, Jul 2, 2004.

  1. riddlej

    riddlej New Member

    Joined:
    Jul 2, 2004
    Messages:
    5
    Likes Received:
    0
    Hope somebody can answer a this question, I have a 1979 FXEF that I bought new, the bike has 15,000 miles and in excellant condition. The original carburator was replaced with an S&S a couple of years ago. There was no place to hook up the crankcase breather hose, so the hose was cut off about 5 inches from the crankcase. The bike runs great, but when the bike sets up for the winter, some how oil settles in the bottom of the crankcase, when I first turned the engine over after it had not been ridden I blew out a half of quart of oil, out the crankcase breather hose and onto the ground. After the engine ran for a couple of minutes, no oil came out, runs great, the running of the engine must prevent the oil from building up in the crancase, the past couple of days I cranked the bike and no oil blown out. Question what causes all that oil to settle in the crankcase after the bike sets up for long periods,. Is this normal, I cant imagine dumping that much oil into the air cleaner and carburetor if it was still hooked up.
  2. hotroadking

    hotroadking Super Moderator Staff Member

    Joined:
    Jun 16, 2004
    Messages:
    13,682
    Likes Received:
    584
    Location:
    Mouseville USA
    Sometimes in the winter these bikes should have a checkball that keeps the oil from flowing back into the crankcase, if this sticks (not sure about your year but I'm aware of this on later EVO's) then oil seeps past all winter and fills the bottom, you start it and it pukes oil.

    I probably won't do that all riding season as you start it more often so less oil slips past.
  3. Seahag

    Seahag New Member

    Joined:
    Mar 31, 2004
    Messages:
    384
    Likes Received:
    0
    Location:
    Mankato, MN
    I have a question

    How can you have a bike for 25 years and only have 15,000 miles if it was in good running condition? :confused:
  4. DaveFxst

    DaveFxst New Member

    Joined:
    Apr 2, 2004
    Messages:
    52
    Likes Received:
    0
    Breather hose

    I have no idea if this will help, however my '91 EVO sportster would do the same thing. Scared the crap out of me first time. A shop mechanic told me it was due to oil seeping past the ball check valve over the winter and to clamp off the oil feed line from the bottom of the oil tank each fall when I winterized it. The only other option was to drain the oil tank completely, which leaves the inside of the tank open to corrosion. I used a 1 1/2" C clamp and a piece of sidewall from a car tire to pinch the line shut. It stopped the problem completely. If you do this, make sure you leave a note taped to the saddle so you remember to take the clamp off in spring.
  5. panhead

    panhead New Member

    Joined:
    Jul 5, 2004
    Messages:
    7
    Likes Received:
    0
    Crankcase breather

    So what have we learned here, is a crankcase breather necessary, or can you safely run without one and just put a filter element on the hose, I have done this but don't know if it is "the right thing to do" :)
  6. hotroadking

    hotroadking Super Moderator Staff Member

    Joined:
    Jun 16, 2004
    Messages:
    13,682
    Likes Received:
    584
    Location:
    Mouseville USA
    I run the head breather bolts to a hose and to a filter behind the trans, it keeps the oil mist out of the motor, IMHO keeps the air cleaner as it enters, yeah it polutes but it's just me ;)

    I got HD's Califorinia models charcoal canister line it's a hard line that follows the frame shape and runs under the tank from the carb area to behind the trans, just modified it a bit to fit the breather bolts.
  7. riddlej

    riddlej New Member

    Joined:
    Jul 2, 2004
    Messages:
    5
    Likes Received:
    0
    Thanks on the crankcase breather

    Thanks for the help,

    From all I have read, everyone was right there is a checkball that should stop all engine oil from the oil tank down to the oil pump where the check ball is and then down to the crank case. your solution should work, either drain the oil out of the tank or have a cut off valve spliced into the oil line. To answer the other question about the 1979 with 15000 miles, I bought it and decided to have it for a collectors item, and yes it runs better than most new bikes. Just got back from a year tour in the middle east and ordered a 2004 Electra Glide Classic. I guess after 25 years, it proves the V Twin was a good engine.

    Once again thanks

Share This Page