Smoking rocker box

Discussion in 'Softail Models' started by 98fat, Feb 15, 2010.

  1. 98fat

    98fat Active Member

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    Just put a Mikuni HSR 42 on my 98 Evo (Fatboy). Also put on a new set of Vance Big Radius 2 into 1. I had to reverse the breather (one piece chrome tubing) to fit with the Mikuni. When I fire it up in the garage it runs great, but I have some smoke coming off the front rocker box. I let it warm up so it burned anything off I had on the motor. Its not exhaust from the from the front cylinder. Breather problem? Ideas?

    I also tend to wonder if going from my big shots without baffles to a 2 into 1 system with a baffle if the backpressure is bringing a bad or loose gasket to light. I had a bleed down test about a year and one half ago without any problems.
     
    Last edited by a moderator: Feb 15, 2010
  2. NEWHD74FAN

    NEWHD74FAN Experienced Member Retired Moderators

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    My first observation would be to check where the smoke is venting from...if it is oil mist or rich mixture coming from exhaust leak, knowing that you changed the exhaust and have to have everything loose and shove everything tight, working from the front to the back to make sure things don't want to separate from each other...
     
  3. Chopper

    Chopper Senior Member

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    Hey fat, when you say you reverse the breather, you mean you put the curve inward not down? Did you use new sealing crush washer on the breather and make it's not restricted? I'm sure new ex. gaskets are a given, could have been a little oil on the heads from installing the carb & ex? Does it still smokes after being warmed up a few times? Ex. back pressure would not affect any gaskets. Check around breather tube for seepage, I don't remember being able to install that tube back wards.
     
  4. 98fat

    98fat Active Member

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    What I mean is the breather is the one piece chrome tube with one connection for a hose to run to the air cleaner. It leaned in towards the bike with the CV carb (prior to the Mikuni) and the outlet was towards the rear cylinder. I had to flip around so the tube leaned out away from the Mikuni because it was hitting the Mikuni. So now the connection to the air cleaner is toward the front cylinder. I don't think the change should make of difference but wounder if I got the washers incorrect (I think there were three per each side) and it isn't breathing correctly which is allowing pressure to build in the rocker boxes once the engine get warm. How do the washers go on and what should I replace?
     
  5. Chopper

    Chopper Senior Member

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    The washer can't go on wrong, should be 4 with large holes and two with smaller holes? So long as there is one between each point of contact and so long as not oil is leaking out around them they are fine, they can not restrict the breathing, only thing that could is a restriction where it goes into the air cleaner or a kink in the hose. My guess there might have just been some oil left over from the install burning off? Is it still smoking?

    If this is what you are using I seem to remember the bolts were stepped because the breather oppenings had one side larger the the other? Did you do any other mods to it?
    [​IMG]
     
  6. 98fat

    98fat Active Member

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    That is exactly what I am using, so you are saying I need to switch the bolts?
     
  7. Chopper

    Chopper Senior Member

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    No, if everything went together it should be fine, is there any sign of oil leakage around them, and does the bike rocker still smoke after being warmed a few times?
     
  8. 98fat

    98fat Active Member

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    I have not made any mods (except reversing it) and I haven't run it today. I will pull the bolts and try to make sure openings match up. I assume with the banjo fittings I just tighten to spec. If there are two different sizes, does it matter which cylinder is on what opening?
     
  9. Chopper

    Chopper Senior Member

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    No, the way I remember it the smaller hole washers went against the head because the bolt was smaller on the end where it crews into the head. If it's not leaking don't mess with it, they are just banjo fittings tighten to spec, I always use a little 243 on the threads to help lock them.
     
  10. 98fat

    98fat Active Member

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    Thanks for the help, I am going to take back apart and check and then run several cycles to get the motor warm. going to leave the breather open to the air to see if the smoking continues. I will let you all know what I find. Thanks again. :)