1. Hello Guest. You have limited privileges and you can't "SEARCH" the forums. Please "Log In" or "Sign Up" for additional functionality. Click HERE to proceed.

Carb fuel level. Help

Discussion in 'XJ Technical Chat' started by Victor Hugo, Nov 25, 2020.

  1. Victor Hugo

    Victor Hugo New Member

    Messages:
    17
    Likes Received:
    7
    Trophy Points:
    3
    Location:
    Mexico
    Hi, I'm setting the fuel level on my xj700x, the manual is not very clear on where to check the fuel level on Mikuni carbs. Should the level be measured up to the carburettor body as in example A (red) or should it be measured down to the gasket contact surface as in example B (green)?

    My specification is 3mm +/- 1mm
     

    Attached Files:

  2. Mezzmo

    Mezzmo Active Member

    Messages:
    110
    Likes Received:
    77
    Trophy Points:
    28
    Location:
    Australia
    Hi, Check my video as it should answer your question...
     
    Victor Hugo likes this.
  3. hogfiddles

    hogfiddles XJ-Wizard, Host-Central NY Carb Clinic Moderator Premium Member

    Messages:
    14,626
    Likes Received:
    5,008
    Trophy Points:
    113
    Location:
    near utica, new york
    Victor Hugo likes this.
  4. cds1984

    cds1984 Active Member

    Messages:
    902
    Likes Received:
    195
    Trophy Points:
    43
    Location:
    Perth, Western Australia
    Damn, good question.
    I have always gone by the side of the carb, In your picture 'A'.
    Pretty that is correct.
    and, more importantly, it works for me!
     
    Victor Hugo likes this.
  5. Victor Hugo

    Victor Hugo New Member

    Messages:
    17
    Likes Received:
    7
    Trophy Points:
    3
    Location:
    Mexico
    After reading over and over again, I came to the conclusion that the correct place to measure is from B.

    The manual says:

    upload_2020-11-27_14-55-50.png

    And I think the bottom edge of the carb body is where the gasket is.

    I hope I'm not wrong.
     
  6. hogfiddles

    hogfiddles XJ-Wizard, Host-Central NY Carb Clinic Moderator Premium Member

    Messages:
    14,626
    Likes Received:
    5,008
    Trophy Points:
    113
    Location:
    near utica, new york
  7. hogfiddles

    hogfiddles XJ-Wizard, Host-Central NY Carb Clinic Moderator Premium Member

    Messages:
    14,626
    Likes Received:
    5,008
    Trophy Points:
    113
    Location:
    near utica, new york
    The gasket is on the top edge of the bowl......the top edge of the bowl and the gasket both sit up into the bottom of the carb body a little bit. That’s why we use the visible bottom edge of the body as a reference point——-since we can see that.
     
  8. Victor Hugo

    Victor Hugo New Member

    Messages:
    17
    Likes Received:
    7
    Trophy Points:
    3
    Location:
    Mexico
    I'm confused again, are you telling me that the correct place is A in my image?

    I read your manual and saw that the bowl and gasket sit up into the bottom of the carb body, but my carb is different than the carb on your manual.

    On my carb you can see the gasket.

    upload_2020-11-27_17-17-1.png

    The difference between A and B (top of the bowl) is a little more than 2 mm.

    upload_2020-11-27_17-17-54.png

    I guess another way of looking at things is that the fuel level should be 3mm below the top of the bowl, that's why I'm measuring from B. But I don't know if I'm wrong or right.
     
  9. hogfiddles

    hogfiddles XJ-Wizard, Host-Central NY Carb Clinic Moderator Premium Member

    Messages:
    14,626
    Likes Received:
    5,008
    Trophy Points:
    113
    Location:
    near utica, new york
    Did you read the PDF?
    Did you read the PDF?
    Did you read the PDF?
    Did you read the PDF?

    MEASURE FROM THE BOTTOM OF THE CARB BODY

    MEASURE FROM THE BOTTOM OF THE CARB BODY

    MEASURE FROM THE BOTTOM OF THE CARB BODY

    MEASURE FROM THE BOTTOM OF THE CARB BODY
     
    Mechanic1978 likes this.
  10. XJ550H

    XJ550H Well-Known Member Premium Member

    Messages:
    13,199
    Likes Received:
    3,854
    Trophy Points:
    113
    Location:
    Great North Woods
    Bump. Shows where to measure from on the x
     
  11. Polock

    Polock Well-Known Member

    Messages:
    9,751
    Likes Received:
    2,093
    Trophy Points:
    113
    Location:
    Beaver Falls, PA
    [​IMG] measure from the green part
     
  12. Toyobaru866

    Toyobaru866 Active Member

    Messages:
    180
    Likes Received:
    43
    Trophy Points:
    28
    Location:
    Netherlands
    Ok, that's a clear answer. Just to satisfy my curiosity, where did you find the information that this is the point to measure from? I don't doubt you knowledge of course :)
     
  13. Polock

    Polock Well-Known Member

    Messages:
    9,751
    Likes Received:
    2,093
    Trophy Points:
    113
    Location:
    Beaver Falls, PA
    ? maybe chacal, maybe hogfiddles, rick-co-matic or bigfitz, it's been awhile
    that's your first mistake :)
     
    Toyobaru866 and Franz like this.
  14. Toyobaru866

    Toyobaru866 Active Member

    Messages:
    180
    Likes Received:
    43
    Trophy Points:
    28
    Location:
    Netherlands
    Hahaha, thanks!
     
  15. hogfiddles

    hogfiddles XJ-Wizard, Host-Central NY Carb Clinic Moderator Premium Member

    Messages:
    14,626
    Likes Received:
    5,008
    Trophy Points:
    113
    Location:
    near utica, new york
    Make sure your not measuring from the top of the ridge though..... you need to measure from the FLAT part
     
  16. Toyobaru866

    Toyobaru866 Active Member

    Messages:
    180
    Likes Received:
    43
    Trophy Points:
    28
    Location:
    Netherlands
    One topic solved! Though it might have been clear for some before now there is no question about it anymore.
    Thanks all for thinking with me on this one.
    Carbs have to come off again...
     
  17. Rooster53

    Rooster53 Well-Known Member Premium Member

    Messages:
    1,852
    Likes Received:
    723
    Trophy Points:
    113
    Location:
    North, FL
    So Polock is saying "B" - wow that was hard.

    So the PDF for wet setting is incorrect then because it shows the measurement from the bottom of the lip - unless you consider x-ray vision and someone is measuring to a point of reference they can't see?

    In the thread - https://xjbikes.com/forums/threads/what-is-correct-float-height.129499/

    MrSeca asked:

    "Thank you for clarifying that, however, you are referring to the "carb body" as the point of reference. Where on the carb body do you measure from? Do you measure from the "carb face" where the gasket rests against OR the "lip" of the carb body that drapes over the carb bowl?"

    jayrodoh replied:

    "Lip over the bowl. Green dot in your first pic."

    So no one saw the need to correct jay? Perhaps because he was correct in his response?

    Are all the factory service manuals wrong, as they clearly show the measurement being done from a visible point on the carb, the bottom of the skirt? They did get the reference designator wrong for "4" and "5."

    XJ700N Air Cooled HSC-33

    upload_2021-7-5_7-52-18.png

    So the lip / skirt on the Hitachi carb is about 2mm tall, does anyone really believe that an error of 2mm will affect the performance of the bike? Say for example, if wet set 2mm low making it lean would you speculate that the pilot mixture screw would go from 2 turns out to 4 turns out to compensate for the low fuel level?
     
    Last edited: Jul 5, 2021
  18. Toyobaru866

    Toyobaru866 Active Member

    Messages:
    180
    Likes Received:
    43
    Trophy Points:
    28
    Location:
    Netherlands
    This is about the carbs for the X, there Mikunis BS33.
    They have a lip on the corners and sides but not on the front and back of the carbs so the bottom of the body is visible to measure from.
    For the Hitachis I believe you measure from the bottom of the lip of the carb body.
     
  19. Toyobaru866

    Toyobaru866 Active Member

    Messages:
    180
    Likes Received:
    43
    Trophy Points:
    28
    Location:
    Netherlands
    Today I've set the fuel level all to 3-3,5 mm below the carb body (green flat part in the last pic posted). Start great and idles steady without choke after 1 to 2 minutes. Didn't have a change to take her for a ride yet.
     
  20. Toyobaru866

    Toyobaru866 Active Member

    Messages:
    180
    Likes Received:
    43
    Trophy Points:
    28
    Location:
    Netherlands
    Yeah, it's a pity this simple answer wasn't given before, would have saved me time. On the other hand people are trying to help others selfless and that's a great thing on this forum.
     

Share This Page