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Hitachi HSC32

Discussion in 'XJ Technical Chat' started by sybe, May 14, 2020.

  1. sybe

    sybe Active Member

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    In my sheer boredom i decided to optimize my carbs a bit more for pods and I wanted to see if emulsion tubes for the HSC32 was was inter changeable with other bikes like the xv750 or xv1000?

    I am also looking for odd sized jets, beside jetsrus, is there another place that would have #46 or #47 pilot and #130 main? Needle jets too!
     
  2. XJ550H

    XJ550H Well-Known Member Premium Member

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    www.xj4ever.com he is our suppoeting vendor and could possibly answer the question.

    the emulsion tubes asperate the fuel. it looks like all the hatachi carbs for 650 and 750 use the #3.2 . I do not think you would gain anything by changing them. more air?

    partzilla shows them only being used in the 650 and 750 for the current size
     
  3. Minimutly

    Minimutly Active Member

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    You're right, emulsion tubes aspirate the fuel - or emulsify it. But, things are never that simple. They have air in the space above the fuel, letting air in the holes into the fuel as it's pulled up from the jet. That's fine, but as speed and load goes up, fuel demand, and use goes up, lowering the fuel level in the emulsion tube. Hence the ratio of fuel to air at different demand can be modified. On Weber sidedrafts tuning by changing these tubes is one tool thats used, but it's little understood, and generally people go on "tube x works well in application y".
    I'm not aware of any charts for Hitachi carbs showing the varying effect of different tubes - so guesswork then?
     
  4. XJ550H

    XJ550H Well-Known Member Premium Member

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    could be that when at higher rpms the chamber is full of air as the fuel sucks into carbs.
    it would also make sense that if you changed asperator tubes you would also change air jet
     
  5. sybe

    sybe Active Member

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    emulsion tubes have different pin hole patterns per engine size and can potentially help the bog people complain about.

    xv650 -900 has 5 holes 3 & 2 on the tubes. xv1100 has 7 holes on the emulsion tubes in a pattern of 3 & 4.

    I'll take a gamble on a set from ebay see if the fit. the jet sizes I am asking for are not the normal sizes. Lens list doesn't have the sizes I am looking for.
     
  6. XJ550H

    XJ550H Well-Known Member Premium Member

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    ye of little faith
    HCP10611 Aftermarket Hitachi brass #130 MAIN FUEL JET, not an original size, used for fuel mixture tuning purposes only, each:

    HCP9815 Aftermarket Hitachi brass #46 PILOT FUEL JET, not an original size, used for fuel mixture tuning purposes only, each:

    HCP9816 Aftermarket Hitachi brass #47 PILOT FUEL JET, not an original size, used for fuel mixture tuning purposes only, each:

    just had to scroll down past stock jets
     
  7. Minimutly

    Minimutly Active Member

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    Hmm, maybe put them to one side and fit some MIKUNIS!
     
  8. chacal

    chacal Moderator Moderator Supporting Vendor Premium Member

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    What engine are you trying to service?
     
  9. XJ550H

    XJ550H Well-Known Member Premium Member

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    you could try enlarging holes or adding holes
     

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