Author Topic: 1980 CB750F Turn Signal - Brake light voltage drop  (Read 503 times)

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Offline mrmach5

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  • 75 Honda 550k, 78 750K, 80 750F, 83 1100F
1980 CB750F Turn Signal - Brake light voltage drop
« on: June 01, 2024, 10:47:44 AM »
So a while back , I had a charging system failure on this bike that I was eventually able to get sorted out . I have a temporary volt gauge up on the handle bars so could monitor charging. Making sufficient voltage at above 3500 rpm , however seems like I have lots of parasitic voltage loss. I installed a LED headlight which helped a bunch as far as draw on the system, however turn on the turn signals and I lose a full volt each time it blinks. Hit the brake light and another volt. So sitting at an intersection, turn signal on, and low charging at idle, it then takes a while for the system to recover. I've been in the headlight bucket and other places checking connections, and nothing obvious.
Vintage CB750 Supply offers a new wiring harness so I may go down that road, and perhaps look into new handle bar switches?
It's always something !!!!!

Offline willbird

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Re: 1980 CB750F Turn Signal - Brake light voltage drop
« Reply #1 on: June 02, 2024, 06:02:32 AM »
I’m not sure if OEM system will charge at idle with headlight, brake light, and turn signals on ?? with old dying batteries on some vintage Hondas hitting brakes with head light on would kill the bike, that bike was a CL175 that liked to boil batteries dry