Honda Cbf125 Electrics

Discussion in 'Technical Help' started by Cyborgbot, Nov 13, 2021.

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  1. Cyborgbot

    Cyborgbot Guest

    I had an issue with my last post but thank you to @Tigcraft and others for their comments and thoughts.

    What I had posted was about my son’s new (to him) Honda CBF125 learner bike and the main headlights dimming at idle.
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    I was lead to believe that the bikes headlights were 12VAC.

    A few of you offered helpful comments. Thank you.

    It seems that the indicators and console are run from the battery.

    Tail light, front side light and head light are run from the generator and possibly via a rectifier. If the engine stalls the lights go out.

    Looks like I will add DRL at the front and a rear red LED or two run from the battery but switched from the ignition via a relay.

    I might switch all the lights to battery fed but will try to ascertain the current rectifiers specifications to see if I need to upgrade or add a second one.
     
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  2. Cyborgbot

    Cyborgbot Guest

    Hmmm…

    We did another 100 miles today.

    On the return journey the lights went almost totally. No illumination below 6k rpm.

    I think the generator/stator or rectifier has gone.
     
    • Agree Agree x 1
  3. Chainbiter

    Chainbiter Well-Known Member

    Aug 6, 2021
    104
    83
    North Yorkshire
    Whip the cover off and check the stator windings for scorching, if they're black and scorched they may have shorted, which may also have damaged the reggy/rec.
     
    • Thanks Thanks x 1
  4. Kinjane

    Kinjane Active Member

    Oct 15, 2017
    233
    43
    Bristol, Land of Enger
    Check that the male and female connectors between the loom and the reg/rectifier are good. Open up the terminal blocks and make sure every connector within is fully seated and cannot pushed back out of its block.
     
    • Thanks Thanks x 1
  5. Cyborgbot

    Cyborgbot Guest

    I phoned the garage. Less than an hour later they had driven 20 miles and picked up the bike.

    That’s traditional quality service!
     
    • Agree Agree x 1
  6. Cyborgbot

    Cyborgbot Guest

    Got the bike back on Saturday and went for a long cold ride in the rain.

    It needed a new generator coil and a rectifier.

    The lights work find now and don’t dim at idle.

    The answer to my original question is the all lights are 12v DC just some are run from the battery and others direct (via the rectifier) off the generator.

    Problems solved

    Out.
     
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  7. Cyborgbot

    Cyborgbot Guest

    The windings were scorched.
     
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