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Carb rebuilding questions

Discussion in 'XJ Technical Chat' started by Gossomer, Sep 25, 2008.

  1. Gossomer

    Gossomer New Member

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    I have a 1981 XJ650H Maxim that I am repairing. During that process I disassembled the carbs before I bought the manual. In the manual it tells me not to remove the pilot screw as it is preset by the factory. I removed it. Is this a major problem? How do I adjust this within a reasonable budget(ie. no factory tools)?
     
    Gossomer, Sep 25, 2008
    #1
  2. wizard

    wizard Active Member

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    no problem, you need to be able to adjust them, put them back 2&3/4 turns out from bottom to start.
     
    wizard, Sep 25, 2008
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  3. bigfitz52

    bigfitz52 Well-Known Member Premium Member

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    Search for the thread "Rick's Old School Carb Cleaning" and follow it to the letter and you will end up in good shape. Remember, before you embark on any serious carb tuning that you MUST check and adjust your valve clearances (if necessary) first. This is a PITA maintenance task that is often simply ignored because of the hassle (or cost to pay someone to do it.) It's supposed to be done every 5000mi but a lot of these bikes are running around with three times that number of miles and have never had it done. Oh, and +1 for buying a manual right away.
     
    bigfitz52, Sep 26, 2008
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  4. MiCarl

    MiCarl Active Member

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    On the 80 and 81 XJ650 models the correct setting is closer to 1 7/8 turns out.

    In 1982 Yamaha switched to a finer thread pitch on the screws.
     
    MiCarl, Sep 26, 2008
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  5. RickCoMatic

    RickCoMatic Well-Known Member

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    In order to truly do any Fine-Tuning ... you are going to have to be able to make adjustments to those Pilot Air (Mixture) Screws.

    You don't have to worry about removing them.
    To do a flushing-out of the Pilot Fuel and Air Passages its best to have them out, anyway.

    There are four component parts to the Mixture Screws.
    The Screw Body with Needle-tipped end.
    A tension Spring
    A tiny flat washer
    A very tiny O-ring.

    Don't lose anything withdrawing the Pilot Mixture Screws.
     
    RickCoMatic, Sep 27, 2008
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