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.

Diode Block Question

Discussion in 'XJ Technical Chat' started by Praxeus, Feb 20, 2019.

Tags:
  1. Praxeus

    Praxeus Member

    Messages:
    60
    Likes Received:
    26
    Trophy Points:
    18
    Location:
    British Columbia
    So I have read the excellent “ultimate relay” and diode post by Chacal, and I have done a search for information about my question, but I am still wondering something.

    I’ve rigged a new start button which activates (like the original) when the blue/white wire is grounded. Big deal, many of us have done this, I know :D. My wiring diagram shows the blue/white wire running first to the diode block (it goes right into it) and then to the factory start button location. My current arrangement has the blue/white wire simply running to a momentary switch from the solenoid that grounds it to activate, and it is functioning fine.

    Question: how important is it that the blue/white wire leave the solenoid and head to the diode block first? If it doesn’t go to the diode block at all, will this affect the safety relay circuit? Just wondering if I should tie into that blue/white wire on the harness before the switch or if it doesn’t matter. Thanks!
     
  2. jayrodoh

    jayrodoh YimYam Premium Member

    Messages:
    2,522
    Likes Received:
    1,102
    Trophy Points:
    113
    Location:
    Cleveland
    I don't know what bike you have, but on a 650 Maxim the starter switch will also illuminate the oil level light when the starter button is pressed. This is "routed" through the diode to prevent the starter from engaging should the oil level light come on due to the oil level switch being activated. If you can live without the oi level light test, then I wouldn't worry about it.
     
    chacal, Praxeus and Chitwood like this.
  3. Praxeus

    Praxeus Member

    Messages:
    60
    Likes Received:
    26
    Trophy Points:
    18
    Location:
    British Columbia
    It's a 1982 XJ650; it's in my signature :)

    I knew there had to be a reason to connect it in there. I am doing a "restomod" but I am trying to keep all the safety circuit elements intact (not wanting a minimum wiring thing), so I will be attaching the wire. Thank you, jayrodoh!
     
  4. XJ550H

    XJ550H Well-Known Member Premium Member

    Messages:
    13,199
    Likes Received:
    3,854
    Trophy Points:
    113
    Location:
    Great North Woods
    the wire through the diode block is for the oil light test.

    the oil light gets power
    from r/w wire from run switch through the resistor then through the diode to the solenoid l/w wire when starter button is pushed it makes ground for the oil light test.

    if low on oil switch closes light comes on by making ground through the oil switch.
    the diode keeps the starter from engaging when oil goes low, closing oil switch making ground

    650oil.PNG

    starter relay is the solenoid
    .
    if you do not run the L/w wire from starter button to the diode block you lose the test circuit for the bulb. this can be worked around with a diode from radio shack or a second button to test the bulb with

    the resistor you see is also in the diode block
     
    Last edited: Feb 23, 2019
    Praxeus likes this.
  5. Praxeus

    Praxeus Member

    Messages:
    60
    Likes Received:
    26
    Trophy Points:
    18
    Location:
    British Columbia

    Thanks for your reply. Are you saying the bulb itself is essential to the oil cutoff circuit? My new gauge does not have an oil light. If the oil switch is working fine and my safety relay is intact but the L/W wire doesn’t go to the block will the circuit still work? Or is that circuit for the light itself. By the way I have of course been using my XJ650 wiring diagram in the manual, but recently I came across this amazing resource -

    http://lumien.se/stuff/xj550/

    Probably everyone knows about this one. If you are saying the L/W wire to the diode block is merely to power the oil light then I should be okay.
     
  6. XJ550H

    XJ550H Well-Known Member Premium Member

    Messages:
    13,199
    Likes Received:
    3,854
    Trophy Points:
    113
    Location:
    Great North Woods
    the reason oil light is hooked into starter switch is to test the bulb.
    the oil light is powered from run switch and when oil goes low the oil level switch makes ground contact turning on the light.

    your bike will start and run with out the connection

    is it needed ? no but you must check oil every time before you ride


    that is a cool wiring diagram for the seca xj550 some of the info can be used on the 650

    I would at minimum hook up a bulb for the oil when riding.
     
    Praxeus likes this.
  7. Praxeus

    Praxeus Member

    Messages:
    60
    Likes Received:
    26
    Trophy Points:
    18
    Location:
    British Columbia
    Thanks again. Yes, put that diagram up on a big screen and you can make the circuit “glow” :cool:
     

Share This Page