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  1. #1
    CB750 Addict Dave's Avatar
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    Lightbulb LED Lighting conversion

    I'm planning to convert my lighting over to LED. All 4 turn signals and tail lamp. 1974 CB750k

    My main reason for doing this is that the filaments break from vibration within days of replacing the bulbs in my front blinkers. Also, the LED's are brighter and the bulb I'm getting for the tail is even brighter and flashes 3 times before going steady when you hit the brakes.

    The old flasher won't work with LED bulbs so you need to replace it with an LED flasher.

    1157 LED Bulb X4
    FL2-RED LED Bulb Electronic Flasher X1
    1157 LED Bulb w/ Brake Flasher X1

    PS I already run a Cibie Headlamp, possibly not legal in the US but who cares, so I'm not converting the headlamp. The shape of the beam provides higher visibility for me, and less glare to oncoming drivers. If you get one, they come in left or right, make sure to get the correct one for your area.

    I forgot about this when I orginally posted. You have to do some modifications to the blinker indicator lamp wiring for this all to work or, just remove the lamp. I'm no artist but here's a drawing showing before and after I've added 2 diodes. I tore apart an old 12v adapter that plugged into the wall to get the diodes out.

    Click image for larger version. 

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    Update, superbright LEDs now sells a kit for this conversion.
    https://www.superbrightleds.com/cat/...e_Kit,60,6206:
    Last edited by Dave; 06-29-2016 at 10:17 PM. Reason: Corrected diode direction in wiring diagram

  2. #2
    CB750 New Member FrostDesigns's Avatar
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    Hey Dave, thanks for the write up, i just installed some pretty basic bullet style LED turn signals on my 750k8. Im having what seem to be the same problems you had until you figured out altering the wires. I'm assuming since i get power off of both left or both right wires that i need to just run them both into the power side of the LED signal wire and run my own ground off of the LED light? or is my power issue in the flasher relay? i figured i would need a different one. I already have the rear lights wired up and they light up but don't flash. Thanks for any help!!

  3. #3
    CB750 Guru amc49's Avatar
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    Your mod drawing incorrect, you have the diodes blocking any power getting into the bulb, there would be no light there. Turn your diode triangles around 180.

    The flasher is the issue, LEDs do not flow as much power as incandescents and the flasher then does not get enough power to load it enough to flash. Use an electronic flasher made specifically for LEDs.

  4. #4
    CB750 New Member FrostDesigns's Avatar
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    So I shouldn't run the 2 power wires coming off of the bike into the power side of the light and make my own ground to the frame??

  5. #5
    CB750 Addict Dave's Avatar
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    Quote Originally Posted by amc49 View Post
    Your mod drawing incorrect, you have the diodes blocking any power getting into the bulb, there would be no light there. Turn your diode triangles around 180.

    The flasher is the issue, LEDs do not flow as much power as incandescents and the flasher then does not get enough power to load it enough to flash. Use an electronic flasher made specifically for LEDs.
    Opps, I corrected the diode direction, made the sentence about the flasher clearer, and added a picture of a diode for those not familiar with electronics icons.

    The problem is not the flasher. The problem is the way the indicator lamp works. On bikes with a single turn signal indicator lamp the two original wires going to it are both positive. One from the left blinker lamp circuit and one from the right blinker lamp circuit. This works fine with the old flasher but not the new LED flashers, hence the modification required.
    Last edited by Dave; 05-07-2016 at 10:36 AM.

  6. #6
    CB750 Addict Dave's Avatar
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    Quote Originally Posted by FrostDesigns View Post
    So I shouldn't run the 2 power wires coming off of the bike into the power side of the light and make my own ground to the frame??
    If you mean the two wires that originally go to the indicator lamp then yes but, you must add the 2 diodes inline or all 4 blinkers will flash at once.

    You must replace the old flasher with an LED flasher too. Make sure you hook up the flasher correctly the 1st time. It will burn out instantly if you get the wires backwards.
    Last edited by Dave; 05-07-2016 at 10:52 AM.

  7. #7
    CB750 New Member ALPHASMURF's Avatar
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    I have a all in one tail light and turn signal and there are only 2 wires for the blinker setup. do i need a 2 diodes per line then?

  8. #8
    CB750 Addict Dave's Avatar
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    Quote Originally Posted by ALPHASMURF View Post
    I have a all in one tail light and turn signal and there are only 2 wires for the blinker setup. do i need a 2 diodes per line then?
    The diodes are for the turn signal "indicator" lamp up near the gauges.

    Your all-in-one tail lamp will wire up just like the original parts. If it has LED lamps in it, you will need the LED flasher and indicator lamp wiring mod.

    (Assuming your talking about an early model CB750 with a single indicator lamp)

  9. #9
    CB750 Member Ron1's Avatar
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    Hey guys! Where is the flasher located? Also, what do I do if my bike has two signal indicator bulbs (one right and one left). I have a 1977 CB750K. Thanks!

  10. #10
    CB750 Addict Dave's Avatar
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    Depends on what bike Ron. Separate L/R indicators won't require any mods.
    96% of the time I edit my replies so check back for updates if it isn't at least an hour old

  11. #11
    CB750 Member mrtelec's Avatar
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    Frostdesigns did you ever get your led's working? I am going through my k8 right now and will be trying to tackle the turn signals next. do you remember what you used and what if any mods you may have done. thank you

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