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First Cafe Racer Mod! 1983 XJ750 Maxim

Discussion in 'XJ Modifications' started by May_J_Aaron, Jun 24, 2018.

  1. Polock

    Polock Well-Known Member

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    put a connector on the headlight ground wire someplace handy, so you can turn the headlight off if you need to
     
  2. May_J_Aaron

    May_J_Aaron Josh May

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    Like running from the cops??? :p
     
  3. Polock

    Polock Well-Known Member

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    well you might need the key on to get that Acewell sorted out or turn signals, don't need a headlight for that sort of thing
    for police you want to turn off the tail/brake light :)
     
  4. May_J_Aaron

    May_J_Aaron Josh May

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    Curious what this little box is, I’m not good enough at reading electrical diagrams to figure this one out... (circled in red)
    833E765D-2A26-406D-9763-9A35914629B0.jpeg
    There a black/red stripe wire (marked in yellow) crossing over to what was the stock gauge cluster warning lights, pretty sure it’s a Ground wire that I don’t need anymore, strongly contemplating cutting it away since all the sensors use the Ground connected to the new Acewell Gauge.
    4A7883FC-968C-457A-B256-117734861CF7.jpeg
    comes to the connector before the box as Blk/red, becomes dark green, then a new blk/red crosses over like I mentioned previously
     
  5. dkavanagh

    dkavanagh Well-Known Member Premium Member

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  6. May_J_Aaron

    May_J_Aaron Josh May

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  7. dkavanagh

    dkavanagh Well-Known Member Premium Member

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    Do you have a schematic w/ wire colors labeled? That helps a lot!
     
  8. Rooster53

    Rooster53 Well-Known Member Premium Member

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    That is the diode block, it's the 2nd picture in the Ebay link. The B/R wire was used for the oil light, one goes to the oil switch and the other goes to the oil indicator light. The diode is used to isolate the circuit from the starter solenoid circuit and to illuminate the oil light when the starter button is pressed.
     
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  9. May_J_Aaron

    May_J_Aaron Josh May

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    ah! Thank you!
    So is it the ground wire for the oil light?
    My Acewell gauge has a ground wire for it, so everything uses that now, the oil light works in the new gauge when I tested it along with the other signal lights.
    Would that mean it’s ok to clip this wire off to free up this rats nest?
     
  10. Polock

    Polock Well-Known Member

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    sure clip it off but don't throw it away :)
     
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  11. Polock

    Polock Well-Known Member

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    how did you hookup that tach? wrap the wire or right to the coil
     
  12. May_J_Aaron

    May_J_Aaron Josh May

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    I haven’t hooked up the tach yet, it mentions wrapping it around a wire...
    I’m waiting on my carbs from Dave Fox to fire it up again.
    What is more reliable? Any issues with wrapping it?
     
  13. Polock

    Polock Well-Known Member

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    reliable ? i guess if it works, it works.
    wrapping a little wire around a plug wire just sounds hokey to me...?
    i used the- side of the coil and a 1meg ohm resistor in series. seal it up good, the tach goes nuts if the resistor gets wet
     
  14. May_J_Aaron

    May_J_Aaron Josh May

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    I thought it sounded odd too!
    Do you have a picture of what that looks like on the side of the coil?
     
  15. Polock

    Polock Well-Known Member

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    get the wire on the coil that goes to the tci box, that's the - side. use a 1 or 1.5 meg ohm resistor
    believe me, you don't want to see my wiring
     
  16. Brandon Spencer

    Brandon Spencer Member

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    This is an awesome write up! I'll be getting the same gauge setup for my XJ750 as I have decided to keep the stock wiring harness for now.

    Keep up the good work!
     
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  17. May_J_Aaron

    May_J_Aaron Josh May

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    Make sure you get the speedo cable adapter on their website! That way you won’t have to use magnets ;)
     
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  18. May_J_Aaron

    May_J_Aaron Josh May

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    Confusion with a dash of newbism...
    I had my carbs professionally rebuilt by the incredible Hogfiddles so it’s time to set the fuel levels for the bowls...
    I got my carbs leveled out with my unique contraption, when I first fill them up I got a reading that filled up slightly below where it should, grab some food to eat, and when I get back it’s over flowing!?...
    What would cause this?
    Using a ruler as well, the upside down “top” of the float is about 16mm.

    newb question- the float needle has a springy rod thing for the float tang, what does the spring action do, act like a buffer???
    830C7D3A-5F79-4195-BA27-110F7752A306.jpeg
    FB5FC503-1D50-442D-8E02-C15662299CDB.jpeg
    F3953DB0-1F3B-4708-A8A1-86EE709CF36E.jpeg
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    I tried to fix the images but they keep flipping when I upload them
     
    Last edited: Dec 13, 2019
  19. Polock

    Polock Well-Known Member

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    think of the needle valve/float as a controlled leak rather than a on/off valve. The more or less that tiny spring is compressed, more or less gas leaks through.
    so the operating range of the float should be in the travel of that spring, theoretically while it's running the tang should never let all the pressure off the spring.
    i never noticed before but if your measurement is right, the float is even with that brass tube? that might be a clue.
    try to keep the measuring tube close to the bowl, less chance for eyeball error
    the floats leaked a bit, was it on a vacuum petcock? did you smack the bowls a few times to vibrate the needles in, like your engine is going to?
     
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  20. May_J_Aaron

    May_J_Aaron Josh May

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    That was my initial thought but when I inspect it, the needle drops down, still resting on the tang, allowing large amount of fuel to flow in quickly (empty bowl), then the tang would push the needle to the top fully engaged (full bowl), then any more fuel (overflowing bowl) would simply add additional pressure through that springy rod within the needle as it’s already been fully pressed up...
    The “controlled leak” does make a lot more sense and may save my sanity with this step!

    That’s a good observation about the siphon tube/ brass tube, they’re very close but it just slightly below the float by about 2 mm.

    No vacuum petcock, just an auxiliary gas tank setup that does have an on/off, bought it at Oreillys.
    D1715915-2A85-46EB-B1BB-29884749FB0F.jpeg
    ~~~~~~~~~~~~
    I got them dialed in after 5 adjustments to 3-3.5 mm depending on the meniscus reading and the suggestion about smacking the carbs made a difference as I got a couple weird readings, tapped it with the Allen wrench and then it was good!
    Highly recommend using an LED light under the tube in the work area to light up the meniscus so it’s easier to see!
     
    Last edited: Dec 15, 2019

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