Forums 🚥 PIT STOP 🔧 Hyosung Technical Help Fun and games with a GT125R

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    • #6450
      Ben
      Member
      • Topics: 1
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      Sep 9, 2021
      @tofuman
      West Yorkshire
      GT125R

      Hello everyone,

      I’m hoping someone could shed some light on an issue i’ve run into while working on my son’s bike. Firstly, she won’t start anymore. No crank, just the starter relay clicking. But on the instrument panel I’ve lost the Neutral light, Full beam light and Indicator light but otherwise the guages work and the lcd display works. I’m thinking the CDI unit has died as I tested it last night and got some weird readings and then none from other. Things I’ve recently done to the bike is: Stripped and rebuilt the carbs. Replaced the Magneto/ Rectifier/ Upgraded HT coils/ Ngk laser plugs/ K&N airfilter/ New battery. We bought this bike a few months ago and it has certainly been played with over the yrs! I also checked the Kick stand switch as it has been bypassed but poorly. So reconnected and wrapped with tape. But after spending over £400 already and now my son has his CBT booked next month, I could do with some guidance before the trusty hammer of thor comes out to play!

    • #6453
      Ben
      Member
      • Topics: 1
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      Sep 9, 2021
      @tofuman
      West Yorkshire
      GT125R

      So no one has any ideas??

    • #6455
      Simon
      Member
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      Sep 9, 2021
      @syco
      Kent
      Gt250 f1

      Have you checked the starter solenoid, there is also the clutch lever switch which can cause issues but starter solinode would be the 1st thing I would look at, you can short across the terminals. If the neutral switch is playing about then the clutch lever switch comes into the mix but the fact the relay is clicking says not but the relay could be at fault its just a case of checking through.

    • #6462
      Ben
      Member
      • Topics: 1
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      Sep 9, 2021
      @tofuman
      West Yorkshire
      GT125R

      I shorted out the solenoid and she cranked over and started, so that’s good news. Ordered a new one. Tomorrow I’m going to remove the gear selector sensor and clean it up etc to see if that returns neutral light but would that also explain why I’ve ls lost the full beam and indicator lits too? Although they do work still. The clutch switch is also on the list on jobs to look at tomorrow. As the harness has been fiddled with to say the least with bits spliced here and there!

      Thanks Simon for your help.

    • #6479
      Ben
      Member
      • Topics: 1
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      Sep 9, 2021
      @tofuman
      West Yorkshire
      GT125R

      Ok so, fitted the new starter relay and tried starting the bike. And then the starter motor would’nt shut off! The black/white cable running to the negative terminal has melted and most of the ground cable in the harness has also melted. So I’m assuming I have a short somewhere along the harness.

      So does anyone have a wiring diagram for the gt125r as I’m starting to loose patients with this thing. Thanks in advance!

       

    • #6486
      Simon
      Member
      • Topics: 0
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      Sep 9, 2021
      @syco
      Kent
      Gt250 f1

      You have definitely got electrical gremlins, in the pit stop section of these forums there are manuals.

    • #6487
      Simon
      Member
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      Sep 9, 2021
      @syco
      Kent
      Gt250 f1

      I suspect the problem lies around the main harness at the instrument/headstock.

    • #6489
      Ben
      Member
      • Topics: 1
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      Sep 9, 2021
      @tofuman
      West Yorkshire
      GT125R

      Gremlins indeed! I’ve been through the service manuals in the pit stop but couldn’t find any wiring diagrams, but I managed to track some down online. I then labeled everything up and remove the harness completely. So the plan is to bell out all the cables and see what I find. If its all ok then I’ll just replace the melted negative cable, but then I know the issue is not with the main harness and the adventure continues.

    • #6493
      Simon
      Member
      • Topics: 0
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      Sep 9, 2021
      @syco
      Kent
      Gt250 f1

      The only things I encountered on my good old 250gt is electrical, I basically have renewed every single connector block with uprated connectors or done away with them completely, I upgraded the rectifier to a shindengen & bypassed the loom (in line fuse of course) direct to the battery, no more gremlins for me touch wood.

    • #6509
      ♠️ MARCEL
      Administrator
      • Topics: 38
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      Joined:
      Sep 9, 2021
      @mf448kxn6
      North UK
      GTR

      Keep us updated, as i have eyes on this topic and have responded to your email , i do hope the main harness is salvageable to be saved and like simon says go ocd with it or least go crazy with the tape and also ACF50 is a good friend to prevent weather turning  gold terminals of (any) connector in to yucky green which signals or electrical juice won’t pass through efficiently  (oxidization of terminals does happen)  , winter sucks (hence we do things to make their life easy and we don’t fancy having to take something apart every week in the ice cold!)  but summer is great.

      // Meditation doesn't mean you have to sit still....

    • #6542
      Ben
      Member
      • Topics: 1
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      Joined:
      Sep 9, 2021
      @tofuman
      West Yorkshire
      GT125R

      Ok so a little update. The harness is repaired and I continuity tested every connection. So the harness is good. Also replaced the No.1 diode which is on the neutral circuit. I’m currently waiting for a new starter motor and neutral switch, but still can not understand why i’ve lost the lights on the display! Indicators, full beam and the neutral light.

      Marcel – I have replied to your email with info for the harness and display.

    • #6547
      ♠️ MARCEL
      Administrator
      • Topics: 38
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      Joined:
      Sep 9, 2021
      @mf448kxn6
      North UK
      GTR

      In regards to the TALE TELLE lights above the LCD Screen…]

      Full Beam = Powered directly via switch gears
      Indicators = Harness & Switch gear signals sent to dash.
      Neutral = Your new incoming sensor should bring the green N light back on

      Also the dash has its own mini harness trunk that deals with lights too. Have you checked the mini harness ?

      // Meditation doesn't mean you have to sit still....

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