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carb sync/exhaust temp

Discussion in 'XJ Technical Chat' started by scottybm1, Aug 3, 2011.

  1. scottybm1

    scottybm1 Member

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    Just got my carbs cleaned up after an 8 year hibernation with old fuel in the bowls. The bike runs but I know she needs a sync. Pipes 1-2 are at about 146 degrees after a short ride, 3-4 are at 97 degrees. I'm guessing 3-4 are richer? I'm going to make my own carb sync tool but is there a way to ball park it until then? Do I need to lean out 3-4 or richen up 1-2? Which way do I turn the screws?
     
    scottybm1, Aug 3, 2011
    #1
  2. bigfitz52

    bigfitz52 Well-Known Member Premium Member

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    Sync and mixture are two different things. (Pretty much anyway.)

    When you "sync" the carbs, you adjust the throttle stop positions on carbs #1, #2 and #4 so that they all produce the same "vacuum signal" as #3, the baseline carb.

    Leaning/richening (the mixture screws) is a different adjustment; you do that AFTER they're sync'ed; you set them all to a baseline of 2 1/2~3 turns out to do the sync; THEN start tweaking mixtures. Tweak them too much and you'll have to go back and re-sync; so they are "related" but like I said, two different procedures.

    YOU CAN'T DO ANY SYNC ADJUSTING UNTIL THE VALVES ARE IN SPEC.

    So, about those valves...
     
    bigfitz52, Aug 3, 2011
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