Natural Light on when clutch is depressed and when bike is stationary (in gear)

Discussion in 'Mechanics Garage' started by stubstunner, Jul 9, 2016.

  1. stubstunner

    stubstunner New Member

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    I just finished putting in a new starter motor. I noticed something funky going on, the neutral light is on when I turn on the bike (not starting, just electric) in gear. As soon as I start rolling and let off the clutch, the light goes out. When I depress to upshift/downshift, light comes on. I haven't changed any of the wiring - it used to be that the light was always off unless I was actually in neutral. It's the strangest thing. I don't usually look at neutral as I am accustomed to dirt bikes with no indicator. I've noticed no other issues. What on earth could be causing this?
     
  2. jev.

    jev. over there

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  3. stubstunner

    stubstunner New Member

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    Chances are that not changing it won't make a difference correct? :D I'll change it, I know exactly where it is, but I'm literally (not metaphorically) about to go for a ride right now.
     
  4. jev.

    jev. over there

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    It doesn't matter either way. It just bugged me enough to change mine.

    It won't hurt anything to leave it be.
     
  5. stubstunner

    stubstunner New Member

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    Thanks jev!
     
  6. squirrelman

    squirrelman Member

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    It's an indication of a bad diode, not usually called a rectifier.
     
  7. jev.

    jev. over there

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    Except in this case, it's exactly what it's called.
     
  8. squirrelman

    squirrelman Member

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    You don't mean the voltage regulator/rectifier ?? That has 3 diodes and has nothing to do with the neutral light or the starter lockout circuitry.
     
  9. jev.

    jev. over there

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    No, check the link. Silicon rectifier is the name Honda gave it.

    Sent from my XT1575 using Tapatalk
     
  10. Allyance

    Allyance Insider

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    The part is actually 2 diodes wired head to head (- to - or + to +, can't remember) with the connection to the neutral switch which control the path to ground. Can send wiring diagram later if you need it. Out for a ride now.
     
  11. jev.

    jev. over there

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    I give up.
    I merely answered the guys question with the correct answer.
     
  12. Allyance

    Allyance Insider

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    [​IMG]

    For Neutral Indicator to light, the wire on the left has to find a path to ground. If the transmission is in neutral, the switch will close, current flows through the bottom diode, through the switch to ground. To prevent the side stand switch and the clutch switch from lighting the indicator, a reversed diode on the other side of the junction (top) blocks any current from finding ground, that is the diode that is bad. Diodes are one type of rectifier, that block dc voltage in on direction and not the other. The common name for the device that rectifies the AC voltage from the alternator (of which the stator is a part) is called the Rectifier/Regulator as the device does both jobs. The R/R is a full wave rectifier to make pure DC from the AC.
    [​IMG][​IMG]
    Location and part #, that's all folks.
     
  13. jev.

    jev. over there

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    That's all well and good, but that's not what is causing his issue. I've had the same part fail on two different Hondas and the diagram I linked to, with the silicon rectifier is the part he needs. But, hey, what do I know. Just been a motorcycle tech for 20 years.

    Sent from my XT1575 using Tapatalk
     
  14. Allyance

    Allyance Insider

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    My bad, I didn't realize he has an 85. Here are some clips from my 83 manual, should be basically the same. Note: it is called the "Silicon Rectifier" in the schematic and the "Clutch Diode" in the manual!!, anyway, this should get him fixed.
    [​IMG]

    [​IMG]

    Sorry you had to change your Avitar!

    PS: Just in case you want to make your own, here is the polarity and pin orientation.
    [​IMG]
     
    Last edited: Jul 10, 2016
  15. jev.

    jev. over there

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    Yeah that's the little bugger. It's only about a 1/2 inch squared. I did exhaustive diagnosing years ago on an ST1100 that I was resurrecting and found the issue to be what Honda calls the silicon rectifier. It always baffled me why it was named that too on the parts fiche. (That was back when we still used microfiche) Anyways, I've ran across the issue a few more times online and on one more of my personal bikes and that has always been the cause.

    I'm sorry about the avatar crap too. Live by the sword....
     
  16. stubstunner

    stubstunner New Member

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    Seems like the contacts had gotten a little cruddy - had the tank off and harness off for a week or so. Pulled it off, used some compressed air and electronic connector cleaner and it was back to normal. Thanks guys!
     
  17. NorcalBoy

    NorcalBoy Member

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    Hahahahahahaha, welcome to the world of "I gave the right answer to the guy 6 posts ago, yet somehow, you can't just let it end". This place is infamous for this.
     
  18. stubstunner

    stubstunner New Member

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    As they say, "it's all good" :) you usually end up getting some other useful info in the other 6 posts haha


    Sent from my iPhone using Tapatalk
     
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