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Thread: What’s up with these carbs???

  1. #1
    Join Date
    Jul 2012
    Location
    Seattle, Washington
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    1,544

    What’s up with these carbs???

    I started tinkering on this 1981 CB400T Hawk to get it running, replaced the battery, ignition switch, cdi, and starting solenoid, etc... Now all the lights, horn, starter all work but it still won’t start.

    After pulling the carb I notice someone used JB Weld on 2 different locations. I am not a real mechanic by any means but I started working on mini bikes last summer and want to learn more.

    Why would anyone do that to a set of carbs? Are these still usable? Should I buy new ones and forget these?

    I found another similar set of carbs from a 1980 CB400, they look similar to mine:

    https://rover.ebay.com/rover/0/0/0?m...2F122704769705

    Click image for larger version. 

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    Theres a a bike shop nearby that does ultrasonic cleaning, I wanted to see if these are even still good to rebuild or not first.

  2. #2
    Join Date
    Jul 2012
    Location
    Seattle, Washington
    --
    1,544
    I just googled my bike specs: http://www.motorcyclespecs.co.za/mod...b400t%2081.htm

    The carbs are 30mm Keihin carbs with accelerator pumps. Would a larger set of carbs help with any type of performance gains? I think the Euro version of this bike had different carbs.

  3. #3
    Join Date
    Jun 2013
    Location
    Oceanside, CA.
    --
    610
    The JB weld has no effect on carb run function, it's the cross tie tube to supply gas to both carbs, single source petcock connection. Does it have spark? If you spray starter fluid does it try to start? Very clean looking bike.

    "HJ" Click image for larger version. 

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  4. #4
    Join Date
    Jul 2012
    Location
    Seattle, Washington
    --
    1,544
    Yes it has spark and will run when sprayed with carb cleaner. I tried turning on the fuel to run the bike but that was before I ordered all the new parts mentioned above.

  5. #5
    AMK's Avatar
    AMK is offline At The Back Of The Pack Arm chair racerFirst time rider
    Join Date
    Jul 2017
    Location
    Shelby, OH
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    181
    Replace the JB Weld with proper O-rings. The PO was just too lazy to pull the carbs and fix it right.
    Alan



    1985 350x
    1984 200es Big Red
    1985 200s (little red)
    1986 200x saga
    2) 1985 350x projects
    And a slew of others to hold my attention

  6. #6
    Join Date
    May 2016
    Location
    OH Canada
    --
    1,102
    I would work with what you have. Give it a good clean.

    Check for fuel flow to the carb. After that should be good to go.
    -------------------------------------------------------------------------------------------------------------------------------------------------------------------

    '83 200X

    Chicks love guys that ride trikes

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