1996 VFR750 odd no start - PLEASE HELP!!

Discussion in 'Mechanics Garage' started by VT Viffer, Sep 19, 2014.

  1. Arnzinator

    Arnzinator New Member

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  2. karazy

    karazy New Member

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    :blue:

    It would be nice to know if it is detectable, or not. One would think that something should show up on the meter.
     
  3. VT Viffer

    VT Viffer New Member

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    I searched for hours trying to find a technique to test a CDI. I found nothing other than, "install a known good unit and if the problem discontinues, the issue was the CDI."

    The FSM doesn't even go into mild troubleshooting for it, and by my understanding, an oscilloscope would be required as well as a functional CDI to use as a baseline. I didn't think that checking the CDIs new vs. old would have been a fruitful project.
     
  4. karazy

    karazy New Member

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    It may not have been, but I didn't think it would hurt to try. If it can save the next guy some time and trouble, then the forum has done it's job. The few minutes spent ringing it out, could have confirmed, or busted the myth that it is untestable.

    If you want to send it to me, I can carry out an autopsy on it.
     
  5. kennybobby

    kennybobby New Member

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    +1 on sending it to the crazy canuck--i believe you will find a short between the power input signal line, pin # xx, and the ground line, pin # yy. Sorry don't have the schematic in front of me just now to give you the exact pin numbers, but a good unit will show an open circuit where the bad one is shorted.
     
  6. VT Viffer

    VT Viffer New Member

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    If you promise to post autopsy pics and results here, I'll send it to you north of the border.

    Email me at krazykarguy@hotmail.com
     
  7. karazy

    karazy New Member

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    Email sent
     
  8. rjgti

    rjgti New Member

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    you can use a huntron to probe it deeper then a scope
     
  9. VT Viffer

    VT Viffer New Member

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    So I finally got to go out on a ride today. Everything seemed to be fine, except that my speedometer and odometer are apparently DOA now. At least this is a relatively simple circuit to test out - it's either the connection at the gauge cluster or the 3p connector behind the tail fairing, the sensor itself, or the speedometer.

    Hoping and praying that it's a simple bad connection, or at worst, the sensor. I really can't continue to toss money at this bike. Dollars per mile are rather staggering this year... 56 miles and well over $300...
     
  10. NormK

    NormK New Member

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    I was rebuilding a 1956 Enfield twin for a mate a few years ago and I used the same dollar per K analysis with him but at that stage I think he was looking at a $100 per k travelled but it has come down now that he is able to get some ks on it
     
  11. VT Viffer

    VT Viffer New Member

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    The sensor tested bad with no output voltage to the cluster when the wheel is rotated. Found a used sensor on eBay last night (listing called it a "gear indicator") for $27 shipped. I hope this evicts the last of my electrical gremlins...
     
  12. VT Viffer

    VT Viffer New Member

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    So the sensor I got didn't fix the issue. The output of the pink sensor wire is nowhere near the FSM specs. 1.15v at most, never near the 4.7 to 5.3 specified. I have tested that the signal wire has continuity and I have 12v at the sensor and at the back of the gauge cluster. I am going to see if I can get some motion out of the speedo needle with a bench test. I am really starting to hate this bike and chasing electrical problems.
     
    Last edited: Oct 25, 2014
  13. VT Viffer

    VT Viffer New Member

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    OK, figured it out:
    [​IMG]

    This is the circuit board behind the speedo. Note the resistor burned to a crisp.

    At what point is Shorai on the hook for this disaster???
     
  14. kennybobby

    kennybobby New Member

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    You may want to check all of those components in the vicinity of that resistor, e.g. the zener diodes. Looks like some over-voltage event and too much current in the resistor. They may be using the zeners as a voltage regulator, seems odd to have 3 of them...maybe you can trace the circuit and draw a schematic to help figure out why it happened.
     
  15. karazy

    karazy New Member

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    If you can still read the colour bands, just use google to figure out what the value is and replace it. It will be easier than getting them to pay out.
     
  16. VT Viffer

    VT Viffer New Member

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    Do they make black resistors with 4 gray bands?

    I am kidding, of course. I had the same thought, but there is no way of identifying the correct resistor.

    I fear that the resistor is not the only damaged component... The component next to it is scorched pretty badly, too.

    This is REAAALLY reaching, but does anyone want to pull apart their '94-'97 VFR and then pull apart their gauge cluster, then pull the circuit board off the speedo to tell me what the resistor's color bands are??
     
    Last edited: Oct 25, 2014
  17. VT Viffer

    VT Viffer New Member

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  18. VT Viffer

    VT Viffer New Member

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    OK, for those of you who have looked at electronic components before, what colors do you see on that resistor in this picture?

    Gold, orange, black, brown? Do these things have 'standard' sizing?

    [​IMG]

    I have been looking for at least 2 hours for this exact picture, finally found one...

    Nobody has anything except full clusters for sale right now - that's too much of a horse pill for me to swallow.
     
  19. kennybobby

    kennybobby New Member

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    It looks like a 1/4 Watt, 10k Ohm resistor, starting at the bottom, Brown=1, Black=0, Orange=3 (x1000), Gold = 5% Tolerance.

    Radio shack has them.
     
    Last edited: Oct 26, 2014
  20. rjgti

    rjgti New Member

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    you are correct kennybobby
     
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