1. Hello Guest. You have limited privileges and you can't "SEARCH" the forums. Please "Log In" or "Sign Up" for additional functionality. Click HERE to proceed.

Not firing on 3 and 4

Discussion in 'XJ Technical Chat' started by EGabe, Oct 22, 2021.

  1. EGabe

    EGabe New Member

    Messages:
    2
    Likes Received:
    0
    Trophy Points:
    1
    Location:
    San jose
    So I have a 82 xj 650 I've replaced the coils new spark plus and caps. I've rebuilt the carbs and cleaned them. I can not get the bike to run on 3 and 4. I've switched the wires and the plugs still nothing. All the cylinders are around 125 only a pound or two difference. Any help is appreciated.
     
  2. bensalf

    bensalf Well-Known Member

    Messages:
    1,274
    Likes Received:
    258
    Trophy Points:
    83
    Location:
    yorkshire ,england
    thats unusual, one coil feeds 1 and 4 cylinders and the other feeds 2 and 3 cylinders , make sure you have the correct leads on the correct plugs.
    are the sp;ark plugs sparking on the cylinders that are'nt firing?
     
  3. JBurch

    JBurch Active Member

    Messages:
    210
    Likes Received:
    90
    Trophy Points:
    28
    Location:
    Owego, NY
    Things to remember: Firing order is 1,2,4,3
    Cylinder order is 1,2,3,4 from left to right as seated on the bike

    Hope this helps
     
  4. XJ550H

    XJ550H Well-Known Member Premium Member

    Messages:
    13,199
    Likes Received:
    3,855
    Trophy Points:
    113
    Location:
    Great North Woods
    ohm between spark plug caps to see if you got the caps screwed on properly.
    that would be between 1 and 4 and 2 and 3,

    check the gap in the plugs

    could be you need to open the mixture screws up a little more for those 2 cylinders.

    you should be using non resistor plugs. no R in the part number
     
  5. EGabe

    EGabe New Member

    Messages:
    2
    Likes Received:
    0
    Trophy Points:
    1
    Location:
    San jose
    Thank for the imput. Sitting on the bike the left coil is 1 and 4 and the right coil is going to 2 and 3. Its got spark in all 4 cylinders. I've switched the coil wires and the caps Played with the fuel mixtures gone as far a 4.5 turns out. The floats seem to be on the money and are set to the 1 and 2 cylinder gas in the float bowls. Could I be off on the floats? The plugs are ngk and set to 30. The only thing i can think is it has to be something with the carbs. I've even done the float test to make sure the floats aren't leaking. Any help of something to check on the carbs is appreciated.
     
  6. XJ550H

    XJ550H Well-Known Member Premium Member

    Messages:
    13,199
    Likes Received:
    3,855
    Trophy Points:
    113
    Location:
    Great North Woods
    have you synced the carbs with bike running?

    have you cleaned the carbs?
    pilot jet circuits could be clogged . could also be the emulsion tubes under main jets are clogged
     
  7. XJ550H

    XJ550H Well-Known Member Premium Member

    Messages:
    13,199
    Likes Received:
    3,855
    Trophy Points:
    113
    Location:
    Great North Woods
    tell us what you have done to the bike. and a few details on how you did things.
    also even with good compresion you still need to check valve shim clearances
     

Share This Page