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yes/no question about main/pilot jet placement

Discussion in 'XJ Technical Chat' started by LeSkid, Mar 9, 2010.

  1. LeSkid

    LeSkid Member

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    background: 82 seca 650 just out of mothballs, currently being resurrected. 14k kms / 9K miles. On Sunday, I did a lazy partial carb cleaning and it immediately sprang to life, on cylinders 1, 2 & 4 only. Very encouraging

    So yesterday I followed Ricks carb cleaning guide. As instructed, when in the float bowl, I noted the main/pilot jet sizes for later re-assembly.

    Except I didn't note which one goes where (sheepish grin)

    yes/no: Is it the larger diameter jets that go into the brass nozzle / needle valve assemblies?


    Reason I ask: It fired-up after my partial cleaning. After doing the 'complete' cleaning (with the questionable jet placement), fuel's getting-in and good sparks when I ground-out the plugs. But this time, it doesn't want to run at all. That, plus my ears are ringing from the gunshots coming out of the exhaust.
     
    LeSkid, Mar 9, 2010
    #1
  2. chacal

    chacal Moderator Moderator Supporting Vendor Premium Member

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    The main fuel jets have the larger diameter hole, and screw into the long brass tube with holes in it (which is called a power valve or emulsion tube or main needle jet....Yamaha likes to call the same part by many different names, depending where you're reading).

    The pilot fuel jets, with the smaller hole, screws directly into the threaded aluminum "post" in the carb body, which is just forward or "in front of" the main jet.


    Up on the top side, the main air jet is the smaller one, and goes directly above the main fuel jet.......so put it into the centre of the three holes.

    The forward hole is for the pilot air jet, which is the larger of the two air jets.

    The rear hole, topside, is for an air jet cover plate hold-down screw. Not all models of the Hitachi carbs used the cover plate (and thus the screw), but all of the bodies are drilled and threaded to accept the screw.
     
    chacal, Mar 9, 2010
    #2
  3. TIMEtoRIDE

    TIMEtoRIDE Active Member

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    That's a yes !
    If it ran before, it'll run again. Did you flood it?
     
    TIMEtoRIDE, Mar 9, 2010
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  4. LeSkid

    LeSkid Member

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    hi Chacal
    so I did get the main/pilot jets right - thanks. Everything else went smoothly thanks to clear & detailed instructions by Rick.

    Yep, flooded. I don't think I overprimed it but the plugs were wet. I'm just worried because after my lazy cleaning on sunday, it started RIGHT AWAY. This time, it wants nothing to do with me.

    That's why I just stopped to make sure I didn't screw-up the main/pilot jets.
     
    LeSkid, Mar 9, 2010
    #4

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