XL250r Carbies fuel level too high

Discussion in 'Thumpers' started by xy500, Mar 21, 2013.

  1. xy500

    xy500 Loser

    Joined:
    Aug 18, 2011
    Oddometer:
    73
    Location:
    Australia, WA
    I've got a problem with a 1985 XL250r, i have been having many problems with the dual carbs. But i've eliminated as many problems as i can, but one remains; too high fuel level in the carbs.

    What happens is the fuel level will reach a good level, then slowly creep up until the level is above the gasket face of the carb bowl. The carbs won't overflow though for whatever reason.
    If i try set the level any lower, no fuel will enter the carb bowls at all.
    I've renewed the floats and needles. This problem happens with both primary and secondary carbs.

    The bike runs great if i shut the fuel off and let the level drop, so the fuel level is definitely a problem. Any insights would be appreciated.
    #1
  2. CycleDoc59

    CycleDoc59 Wrench Rider

    Joined:
    May 24, 2006
    Oddometer:
    984
    Location:
    East Virginia
    I believe the float needle seat on those is
    pressed in with a O ring seal which has likely
    failed. A photo here shows what that would look like:
    http://tinyurl.com/btnsfm7
    Also, does the needle cushion spring work ok?
    If it sticks, it causes float height problems. And,
    sometime the float(s) get bent slightly such that
    the float sides drag...
    #2
  3. xy500

    xy500 Loser

    Joined:
    Aug 18, 2011
    Oddometer:
    73
    Location:
    Australia, WA
    cheers for the insight.
    The carbs on this model don't have removable seats though:
    http://www.servicehondapsn.com/fich...=Motorcycles&make=Honda&year=1985&fveh=131787
    I have checked with the bowls off and the fuel on, when i lift the float to when the spring on the plunger engages the fuel cuts off completely.
    so the seat seems good.
    The secondary float was dragging, but i bent it back straight so thats not a problem anymore...
    Keep throwing those ideas at me!
    #3
  4. Danjal

    Danjal Insert wit here.

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    Possible vacuum in the bowls? There's normally a vent on carbs,could be clogged partially not letting enough air in to offset the vac.
    #4
  5. qkenf4u

    qkenf4u Been here awhile

    Joined:
    Jul 25, 2009
    Oddometer:
    201
    Location:
    nice warm bike riding COTTONWOOD ARIZONA...
    you say you fixed a dragging float.... maybe cut down your bowl gasket (or is it o-ring style on these ??) so it doesnt hold the float up ?
    #5
  6. xy500

    xy500 Loser

    Joined:
    Aug 18, 2011
    Oddometer:
    73
    Location:
    Australia, WA
    The bowls overfill with the motor off, so no vacuum present. I gave them a spray out though just in case

    They're o-ring style rubber gaskets, thankfully as i have had to take the bowls on and off too many times! The float is two piece, and the one of the floats was dragging against the jet holding section in the middle.
    #6
  7. Danjal

    Danjal Insert wit here.

    Joined:
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    2,755
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    Ok,so it's purely a mechanical problem then.
    #7