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Vacuum petcock question

Discussion in 'The Garage' started by TazioliBuilt, Sep 13, 2018.

  1. Does the 2nd fuel line on the petcock supply fuel or it is vacuum only?
  2. BBS360

    BBS360 XS400 Guru

    It just provides the "vacuum" pressure to pull the diaphragm in the petcock and allow fuel to flow to the carbs.
    Should attach to the barb on the left carb boot.
    TazioliBuilt likes this.
  3. So fuel can’t come through it?
  4. BBS360

    BBS360 XS400 Guru

    Should never be any fuel in the petcock vacuum line unless the diaphragm leaks.

    I suppose a tiny amount of atomized fuel could find its way up there and condense.

  5. Thank you. Wasn’t sure if it supplied extra fuel as well during idle or something silly.
  6. xschris

    xschris a lifestyle not a trend

    Is it the stock petcock?
  7. Yes it is.

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