collapse

www.dimecitycycles.com


www.restocycle.com

www.CITYLIMITMOTO.com

www.jadusmotorcycleparts.com

www.bisonmotorsports.com

www.speedmotoco.com

www.cognitomoto.com

www.townmoto.com

www.sparckmoto.com

www.Moto-Madness.com

www.pistonsociety.com

www.steeltowngarage.com


Author Topic: 1975 CB750 - Charging problem  (Read 224 times)

Offline durp

  • Posts: 106
    • One-Offs
1975 CB750 - Charging problem
« on: Aug 07, 2017, 13:05:25 »
Going through the standard procedures, one of the checks I did was on the 3 yellow wires going to/from the generator to the rectifier. According the manual (IIRC) it should ready less than .2 ohms. I made sure the battery was disconnected for this test.

Assuming I did this correctly, and that I have the correct ohms setting selected on my multimeter, it looks like the issue is in the stator/generator. Can anyone confirm I am testing this correctly?





GL1000  GB500  CB750f  CB350f  K75

www.oneoffs.bike

     \_(ツ)_/

Offline irk miller

  • DTT SUPPORTER
  • *
  • DTT BOTM WINNER
  • *
  • Posts: 6717
  • You've been mostly-dead all day.
Re: 1975 CB750 - Charging problem
« Reply #1 on: Aug 07, 2017, 13:46:20 »
Test the resistance for your meter by touching the red and black leads together, then subtract those numbers from your reading on the stator.  I'd be willing to bet you'll get .3 ohms, which puts at least one of your other readings within spec. 

Offline durp

  • Posts: 106
    • One-Offs
Re: 1975 CB750 - Charging problem
« Reply #2 on: Aug 07, 2017, 18:10:42 »
Thanks for the tip. I'll try that this evening and report back.
GL1000  GB500  CB750f  CB350f  K75

www.oneoffs.bike

     \_(ツ)_/

Offline durp

  • Posts: 106
    • One-Offs
Re: 1975 CB750 - Charging problem
« Reply #3 on: Aug 09, 2017, 14:30:54 »
When touch the positive/negative leads on the multimeter, after a few seconds it eventually lands back to 0.0.
GL1000  GB500  CB750f  CB350f  K75

www.oneoffs.bike

     \_(ツ)_/

Offline irk miller

  • DTT SUPPORTER
  • *
  • DTT BOTM WINNER
  • *
  • Posts: 6717
  • You've been mostly-dead all day.
Re: 1975 CB750 - Charging problem
« Reply #4 on: Aug 09, 2017, 15:07:49 »
Really?  Someone smarter than me will have to explain that one.  I thought they all had some resistance in the leads.  Maybe yours is set up to zero out. 

Regardless, you have at least two that are out of spec, which suggests you have a bad stator.  I would check the connectors first.  They heat up, get brittle and go bad.  Next, i'd run the bike with the yellow wires disconnected and test the leads between two yellow wires while it's running.  Voltage should go up with rpms and reach 50 - 60v.  Lastly, I'd test for continuity to ground for each of the yellow wires.  If there is continuity, it's definitely bad.