Author Topic: Headlight only functional in neutral and when clutch is engaged.  (Read 1132 times)

0 Members and 1 Guest are viewing this topic.

Offline Kreb

  • Full Member
  • *
  • Posts: 23
Hey guys,

I just wired up a new headlight on my 76' Cb 550. It looks great but its only lighting up when the bike is in neutral or when the clutch is engaged. I must have wired something up wrong but i'm not sure what it could be. For the headlight I wired in the new socket exactly how the older one was so it is most likely something else thats wrong. Let me know if you have any ideas.

Thanks

Offline calj737

  • Moderator
  • Really Old Timer ...
  • *****
  • Posts: 21,040
  • I refuse...
Re: Headlight only functional in neutral and when clutch is engaged.
« Reply #1 on: June 20, 2019, 08:33:38 PM »
Are you using an m-unit? If so, it’s pretty darn easy to wire it correctly. Pretty hard to wire it wrong.
'74 550 Build http://forums.sohc4.net/index.php?topic=126401.0
'73 500 Build http://forums.sohc4.net/index.php?topic=132935.0

"Of all tyrannies, a tyranny sincerely exercised for the good of it's victim may be the most oppressive. It may be better to live under robber barons than under omnipotent moral busybodies. The robber baron's cruelty may sometimes sleep, his cupidity may at some point be satiated, but those who torment us for our own good will torment us without end for they do so with the approval of their own conscience." - C.S. Lewis

Offline HondaMan

  • Someone took this pic of me before I became a
  • Really Old Timer ...
  • *******
  • Posts: 13,852
  • ...not my choice, I was nicknamed...
    • Getting 'em Back on the Road
Re: Headlight only functional in neutral and when clutch is engaged.
« Reply #2 on: July 05, 2019, 07:15:48 PM »
If stock: the Green-Red wire in the headlight is the Neutral-safety circuit. The headlight is likely using that for its ground, so use a different Green (only) wire for the headlight.
See SOHC4shop@gmail.com for info about the gadgets I make for these bikes.

The demons are repulsed when a man does good. Use that.
Blood is thicker than water, but motor oil is thicker yet...so, don't mess with my SOHC4, or I might have to hurt you.
Hondaman's creed: "Bikers are family. Treat them accordingly."

Link to Hondaman Ignition: http://forums.sohc4.net/index.php?topic=67543.0

Link to My CB750 Book: https://www.lulu.com/search?adult_audience_rating=00&page=1&pageSize=10&q=my+cb750+book

Link to website: www.SOHC4shop.com

Offline ofreen

  • Old Timer
  • ******
  • Posts: 4,020
Re: Headlight only functional in neutral and when clutch is engaged.
« Reply #3 on: July 06, 2019, 09:39:16 AM »
Yes, the headlight is not grounded correctly.
Greg
'75 CB750F

"I would rather have questions I cannot answer than answers I cannot question." - Dr. Wei-Hock Soon