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1980 RM250 Carb issue

Discussion in 'Fuel' started by John Fedor, Apr 18, 2016.

  1. John Fedor

    John Fedor Noob

    Racing Number:
    My 1980 RM250 keeps bogging due to running out of fuel. It starts easily and revs OK but once underwayafter about 30 seconds it runs out of fuel. I wait and can see fuel start to flow again through the in-line fuel filter.I've done the following to solve it but the problem still exists:
    • Cleaned fuel petcock
    • Changed fuel line and in-line fuel filter
    • Installed new float needle assembly
    • Blew out all carb holes and passages. None clogged
    • Installed new reeds
    • No pinched carb overflow lines
    • Floats slide up and down
    Any suggestions?
  2. halffast

    halffast PR Elite

    East Sparta , Ohio
    if Mikuni right ? On some of them you can install the individual - style floats " upside down " so that the little actuating pins ( not always located in the center ) shut off the flow too soon , but I'm not sure if that is the style you have . With a new float needle you may just have to bend the little tang on the yoke so that it doesn't close the needle as soon . I usually set mine with the carb off the bike and blow through the fuel line , setting the floats pretty much " level " with the carb body when the air blowing through is shut off .
  3. John Fedor

    John Fedor Noob

    Racing Number:
    Hi Halffast,
    I have the individual floats and they are installed correctly. Will adjust the tang. Thanks for the suggestions
  4. msinclair

    msinclair PR Member

    Sounds like the gas cap venting that lets in air may be clogged, another idea!
    DTS likes this.
  5. Mike

    Mike PR Addict

    Racing Number:
    John, this may not be the root cause of the issue but it is an issue with old Suzuki's, the fuel petcocks are CRAP, you can use the 44300-28E10 from a late model RM, it flows 2 or 3 time as much fuel and uses a bigger fuel line. As the owner of too many old Suzuki RM's the first thing I do is throw the old petcock in the trash.

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