« previous next »
Pages: [1]   Go Down

Author Topic: Electrical cut-out CB550  (Read 636 times)

0 Members and 1 Guest are viewing this topic.

Offline 1977_cb550k

  • Full Member
  • *
  • Posts: 71
Electrical cut-out CB550
« on: March 06, 2021, 01:26:19 PM »
Hi folks,
Was all kitted up and ready to ride today with a couple of mates.

Turned the key and the engine/oil/neutral lamps were lit up fine. All normal. And  then 5 seconds later complete cut-out of the indicator lights. Dead.

Checked the fuses. All fine. Tested the battery - 12.7v charge, fine?
Checked visible electrical cables, couldn’t see any issues (my cables are in good nick).

Any clues what would cause that cut-out but not burn a fuse?
Logged
1977 CB550k3

Offline bryanj

  • Really Old Timer ...
  • *******
  • Posts: 14,134
  • CB500 Number 1000036
Re: Electrical cut-out CB550
« Reply #1 on: March 06, 2021, 02:49:12 PM »
Check the fuses with a metet not just visually, the clips holding the fuses go soft and dont hold the fuses tight which overheats the eend cap and unsolders the element---fuse looks good but no current path.
Hondaman makes a blade type fuse boxdirect replacement
Logged
Semi Geriatric ex-Honda mechanic and MOT tester (UK version of annual inspection). Garage full of "projects" mostly 500/4 from pre 73 (no road tax in UK).

Remember "Its always in the last place you look" COURSE IT IS YOU STOP LOOKIN THEN!

Offline 1977_cb550k

  • Full Member
  • *
  • Posts: 71
Re: Electrical cut-out CB550
« Reply #2 on: March 06, 2021, 04:02:49 PM »
Thanks Bryan.
Replaced all fuses and still no luck.
Logged
1977 CB550k3

Offline Bodi

  • Really Old Timer ...
  • *******
  • Posts: 5,702
Re: Electrical cut-out CB550
« Reply #3 on: March 06, 2021, 05:26:45 PM »
First I would measure battery voltage with the keyswitch on. I have seen several batteries fail so that they read good voltage but can't power anything: some internal failure that causes a very high internal resistance. If it's ok...
Most likely is the keyswitch, the rear plastic housing (the actual switch part) gets brittle and the holding tabs break, then the back comes loose. The harness plug can also work loose.
Or the ground or power cable from the battery has a poor connection. Shorting the starter solenoid studs with a hefty screwdriver will tell if there's power and ground for the starter, at least.
If no starter spin, look into the battery cables for ground and battery pos. If it does spin... the harness battery power wire (red with an extra insulating sleeve) goes from battery pos to one end of the MAIN fuse, either directly or from the solenoid input stud. So if you have no voltage from battery neg to the fuse ends, check that power wire.
And look inside the fusecase, the back pries off. Overheating from poor connection to a fuse (MAIN carries the most current) can melt the solder so the wire falls off or gets an intermittent connection, can even arc and burn away.
« Last Edit: March 07, 2021, 03:09:25 PM by Bodi »
Logged

Offline goodtryer

  • Hot Shot
  • ***
  • Posts: 494
Re: Electrical cut-out CB550
« Reply #4 on: March 06, 2021, 07:47:51 PM »
Logged
"Tolerance will reach such a level that intelligent people will be banned from thinking so as not to offend the imbeciles."
-Dostoievski

1977 CB550K
1978 CB750K
1973 CB500K

Online newday777

  • Really Old Timer ...
  • *******
  • Posts: 5,582
  • Avatar is my 76 K6 in Colorado w/Cody on back 1980
Re: Electrical cut-out CB550
« Reply #5 on: March 07, 2021, 05:26:47 AM »
Do you have an Emgo ignition switch on the bike?
Logged
Stu
Honda Parts manager in the mid 1970s Nashua Honda
My current rides
1975 K5 Planet Blue my summer ride, it was a friend's bike I worked with at the Honda shop in 76, lots of fun to be on it again
1976 K6 Anteres Red rebuilding project, was originally my brother's that I set up from the crate, it'll breath again soon!
Project 750s, 2 K4, 2 K6, 1 K8
2008 GL1800 my daily ride and cross country runner

Prior bikes....
1972 Suzuki GT380 I had charge of it for a year in 1973 while my friend was deployed and learned to love street riding....
New CB450 K7 after my friend returned...
New CB750 K5 Planet Blue, demise by ex cousin in law at 9,000 miles...
New CB750 K6 Anteres Red, to replace the totaled K5, I sold this K6 at 45k in 1983, I had heavily modified it, many great memories on it and have missed it greatly.....
1983 GL1100A, 1999 GL1500 SE, 1999 GL1500A

Offline evinrude7

  • not a kung-fu
  • Master
  • *****
  • Posts: 2,099
  • something to hüsker
Re: Electrical cut-out CB550
« Reply #6 on: March 07, 2021, 05:42:00 AM »
ignition switch
Logged
cb750 k6 - ugly

Offline Shtonecb500

  • Master
  • *****
  • Posts: 1,652
    • Youtube profile
Re: Electrical cut-out CB550
« Reply #7 on: March 07, 2021, 09:15:22 AM »
most of my problems like that have been my ignition switch going dead, its happened to me 3 times.
Logged
73/74'' CB500/550 resto-mod - sold
75' 750f 91' cbr f2 swap cafe - mock up
74' 750 chopper hardtail - complete - sold
74' CB750/836kit - Black mix & match - daily rider - always tweaking
71' cb500 K0 survivor - complete
71' K1 - CANDY GOLD/BROWN Winton kit - in process

Offline 1977_cb550k

  • Full Member
  • *
  • Posts: 71
Re: Electrical cut-out CB550
« Reply #8 on: March 07, 2021, 02:38:19 PM »
It's an original ignition switch. I'll check it, and the harness/connections from it - and report back (next weekend).
Logged
1977 CB550k3

Offline 1977_cb550k

  • Full Member
  • *
  • Posts: 71
Re: Electrical cut-out CB550
« Reply #9 on: March 11, 2021, 10:29:55 PM »
OK. got to the bottom of my problem. It wasn't the ignition switch.

The charge system was over-charging at ~16V and it cooked my battery.

Installed new battery and adjusted the points gap slightly to bring charge rate down to 13.7V.

Sorted (for now).
Logged
1977 CB550k3
Pages: [1]   Go Up
« previous next »