crankcase vent

Discussion in 'Dyna Models' started by rjw922, Jul 22, 2009.

  1. rjw922

    rjw922 Member

    My 87' FXLR has an S&S carb with the vent tube routed below the engine with a small breather/filter on the end. My question is that when the bike has not run for a long time, say about six weeks, it pukes a lot of oil out the vent. The previous owner did this set up and I know that it should be vented up to the air cleaner. Is this done to prevent fouling the air filter with oil?
    It doesnt appaer to have much blow by or use much oil when run on regular basis.

    NEWHD74FAN Experienced Member Retired Moderators

    Probably a little of both...bottom line, oil venting out "usually" means overfilling, splashing & siphoning due to improper routing of the hose/vent or honest to gosh blowby. That said, check location and routing of the tubing (use longer tubing if necessary above the engine exit aways before letting it exit below, so the oil mist is being vented and not "globs"...BTW what do you consider a "lot"?
  3. 2000classic

    2000classic Active Member

    Ok, now I'm not real familiar with that model of bike so someone correct me if I'm wrong. Seems this is the standard location for the c.c vent. Down below the engine in 1987. Your puking problem comes about if the bike has sat for sometime? If oil tank is up high, you may have a check valve issue which is allowing oil to leak down when bike has not been ridden for a while creating a wet sump. Just guessing.
  4. rjw922

    rjw922 Member

    The service manual shows the vent hose going back to the air cleaner housing, but with the with the S&S carb and air filter the previuos owner ran the vent tube out below the engine. As far as oil fill level, it is between the marks. As far as the amount it pukes, when I started it this spring after storage it dropped about a half quart.
    I thought maybe some one else had seen this before. I will try rerouting the line and see what happens.

    Found an article in the help section about repairing the oil pump check valve seats. This makes sense and is something that I can handle.
    Thanks for replies.
    Last edited by a moderator: Jul 23, 2009