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84 XJ750 41Y jet sizes

Discussion in 'XJ Technical Chat' started by Pieterjan, Oct 9, 2020.

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  1. Pieterjan

    Pieterjan New Member

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    Hello all,

    I recently purchased a 1984 XJ750 41Y (identified with the help of this forum, thanks!).
    Engine ID is: 41Y003003.

    My question is: what are the default jet sizes that correspond to this model? I find conflicting information...
    Currently the carbs have the following specs:
    Needle: Y-18
    Idle jet: 41
    Main jet: 106
    Air jets: 70 & 225

    The bike is running very lean. When cold, it will stall upon throttle input. When hot, it will hesitate a little before revving. To troubleshoot, I lifted the needles a little and that resulted in a much better behavior.

    On the net, I found a carb repair kit with much larger jets, which they state is for a '84 XJ750 41Y:

    Thanks in advance,
    Greetings,
    PJ
     
    Pieterjan, Oct 9, 2020
    #1
  2. Rooster53

    Rooster53 Well-Known Member Premium Member

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    Welcome to XJbikes

    Those appear correct per this source:

    http://xjbikes.wikidot.com/carb-specs

    Any other history on the bike? Have the valves been checked, carbs cleaned, wet fuel levels checked, and carb sync properly done?

    Or, perhaps if running lean intake manifolds cracked or vacuum caps deteriorated and leaking - throttle shaft seals?
     
    Rooster53, Oct 10, 2020
    #2
    k-moe likes this.

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