tw 125 starting but does stay running
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Thread: tw 125 starting but does stay running

  1. #1
    Junior Member drake's Avatar
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    tw 125 starting but does stay running

    bike will start and run only if i keep the starter button pressed as soon as i release the starter button the spark stops and the bike conks out please help

  2. #2
    Senior Member SportsterDoc's Avatar
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    I do not have a schematic, but this reminds me of cars of yesteryear with a ballast resistor.
    When starting, 12 volts went to coil, but when started, circuit went thought a resistor to reduce voltage to points and condenser.
    If symptoms same as yours, ballast resistor failed.

    What can you advise about 125 circuitry/coil?
    Any mods to your stop/run switch circuit?
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    2014 Honda CB1100
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  3. #3
    Junior Member drake's Avatar
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    thank you for the advice i am not good at electrics but i will check this out, thanks again

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  5. #4
    Senior Member christddel's Avatar
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    Quote Originally Posted by drake View Post
    bike will start and run only if i keep the starter button pressed as soon as i release the starter button the spark stops and the bike conks out please help
    Hello,
    There must be a ground in the electrical circuit ...
    Is the neutral indicator light on ?

    Check the circuit in "black color" In the surrounding area on the diagram, (Sorry the schema text is in french)
    Coupure masse Allum CDI TW125.jpg

    The wiring diagram of the TW125

    Schéma ignition TW125.jpg
    Last edited by christddel; 01-10-2019 at 03:04 PM. Reason: complementary
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  6. #5
    Senior Member SportsterDoc's Avatar
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    Without the manual, this is just a guess, but have you tested the ignition circuit cut-out relay (don't know if it would even start if it fails)?
    https://www.tw200forum.com/forum/tec...ual-error.html
    2014 Honda CB1100
    2018 Yamaha XT250
    2016 Moto Guzzi V7 II
    2017 Yamaha TW200
    2012 Triumph Bonneville
    2002 H-D Sportster 1200 Sport
    2003 H-D Sportster 883
    1976 Honda CB750F
    1975 Honda CB360
    1970 Yamaha CT1
    1972 Yamaha CT2
    1972 Yamaha AT2/CT2
    1970 Honda SL350
    1970 Honda CL350
    1967 Honda CL160
    1967 Honda CB160
    1962 Honda CA110

  7. #6
    Senior Member SportsterDoc's Avatar
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    Quote Originally Posted by christddel View Post
    Is the neutral indicator light on ?
    Schéma ignition TW125.jpg
    Good question.
    Are you starting in neutral with clutch also pulled in?
    2014 Honda CB1100
    2018 Yamaha XT250
    2016 Moto Guzzi V7 II
    2017 Yamaha TW200
    2012 Triumph Bonneville
    2002 H-D Sportster 1200 Sport
    2003 H-D Sportster 883
    1976 Honda CB750F
    1975 Honda CB360
    1970 Yamaha CT1
    1972 Yamaha CT2
    1972 Yamaha AT2/CT2
    1970 Honda SL350
    1970 Honda CL350
    1967 Honda CL160
    1967 Honda CB160
    1962 Honda CA110

  8. #7
    Senior Member SportsterDoc's Avatar
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    Found a TW200E manual on-line

    http://www.tw-parts.com/macbig2k1/do...ain_manual.pdf

    See PDF page 240

    TW200E trouble shooting.jpg

    This may not explain the start, but not keep running.
    2014 Honda CB1100
    2018 Yamaha XT250
    2016 Moto Guzzi V7 II
    2017 Yamaha TW200
    2012 Triumph Bonneville
    2002 H-D Sportster 1200 Sport
    2003 H-D Sportster 883
    1976 Honda CB750F
    1975 Honda CB360
    1970 Yamaha CT1
    1972 Yamaha CT2
    1972 Yamaha AT2/CT2
    1970 Honda SL350
    1970 Honda CL350
    1967 Honda CL160
    1967 Honda CB160
    1962 Honda CA110

  9. #8
    Senior Member SportsterDoc's Avatar
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    See manual PDF pages 196 and 197 for schematic and component list.
    2014 Honda CB1100
    2018 Yamaha XT250
    2016 Moto Guzzi V7 II
    2017 Yamaha TW200
    2012 Triumph Bonneville
    2002 H-D Sportster 1200 Sport
    2003 H-D Sportster 883
    1976 Honda CB750F
    1975 Honda CB360
    1970 Yamaha CT1
    1972 Yamaha CT2
    1972 Yamaha AT2/CT2
    1970 Honda SL350
    1970 Honda CL350
    1967 Honda CL160
    1967 Honda CB160
    1962 Honda CA110

  10. #9
    Senior Member SportsterDoc's Avatar
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    I skimmed what seemed to be pertinent parts of the manual (your TW125 may differ) and found no reason for it to crank and start if safety switches are not operating,
    PDF page 200 ignition circuit
    206 neutral switch
    207 ignition cutoff relay
    208 side stand switch
    210 start systgem
    215 start circuit

    Still looking for a TW125 manual
    2014 Honda CB1100
    2018 Yamaha XT250
    2016 Moto Guzzi V7 II
    2017 Yamaha TW200
    2012 Triumph Bonneville
    2002 H-D Sportster 1200 Sport
    2003 H-D Sportster 883
    1976 Honda CB750F
    1975 Honda CB360
    1970 Yamaha CT1
    1972 Yamaha CT2
    1972 Yamaha AT2/CT2
    1970 Honda SL350
    1970 Honda CL350
    1967 Honda CL160
    1967 Honda CB160
    1962 Honda CA110

  11. #10
    Senior Member SportsterDoc's Avatar
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    Found a 2003 TW125 supplemental manual

    Schematic on page 29/29

    http://www.tw-parts.com/macbig2k1/doc/tw125-2003.pdf

    At this point pending answers to how you are starting it, I would check clutch switch, neutral switch and side-stand switches.
    2014 Honda CB1100
    2018 Yamaha XT250
    2016 Moto Guzzi V7 II
    2017 Yamaha TW200
    2012 Triumph Bonneville
    2002 H-D Sportster 1200 Sport
    2003 H-D Sportster 883
    1976 Honda CB750F
    1975 Honda CB360
    1970 Yamaha CT1
    1972 Yamaha CT2
    1972 Yamaha AT2/CT2
    1970 Honda SL350
    1970 Honda CL350
    1967 Honda CL160
    1967 Honda CB160
    1962 Honda CA110

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