Author Topic: Starter turning itself on and other electrical shenannigans  (Read 1393 times)

0 Members and 1 Guest are viewing this topic.

Offline chud

  • Full Member
  • *
  • Posts: 46
Hey guys, I went to ride my 76 cb760F for the first time in about a month yesterday.  While I was kicking it to start it (I always kick it because the starter button hasn't started it since I've had it), the starter came on and started turning over.  I turned the ignition off and the starter still was turning over; then I got off the bike and the starter stopped.  I went ahead and started the bike by kicking and rode around a little and while I was riding, the bike shut down and the starter started turning over again.  I got it started and got back home and noticed several burnt wire covers and exposed wire under the left sidecover area.  I don't see anything that would be shorting across the solenoid posts.  Where else should I look for a short?

Also, since I always kickstart the bike, can I just remove the solenoid.  I'd like to remove as much unused eletrics as possible since they seem to be nothing but trouble for me. 

This bike is not near as nice as most of the ones on here and I know most of you guys would do the job right and fix the starter issue etc., but I'm going to need it for transportation this week and am looking for some ideas for a quick fix.

Thanks for any help.

Offline chud

  • Full Member
  • *
  • Posts: 46
Re: Starter turning itself on and other electrical shenannigans
« Reply #1 on: July 06, 2008, 05:59:28 PM »
After looking through my wiring some more it looks like the red/white wire is the one that really got burned, all the way from the rectifier on up as far as I can see without tearing things apart too much. 

Can anybody tell me what's going on?  Rectifier bad or something else?  Thanks alot.

Offline Hush

  • Finally they realise that I am an
  • Really Old Timer ...
  • *******
  • Posts: 6,761
  • "Lady, I've heard it all before"!
Re: Starter turning itself on and other electrical shenannigans
« Reply #2 on: July 07, 2008, 12:39:24 AM »
Inside your headlight bucket is where all your wiring from the handle bars ends up.
If your 750 is similar (and I think its same across all hondas) to my 650 then you should disconnect the yellow/red wires as they are the starter button wires.
At the starter button on the right hand control these red/yellow wires are pushed onto the black wires (which is only live when ignition is on).
This wont affect your starting as you kick it anyway.
Red/white wires are from your main fuse (down by battery) and go to the rectifier.
As your starter motor is suddenly running when it never has before, disconnecting red/yellow may stop any more melt downs.
I think the thing I most like about motorcycling is the speed at which my brain must process information at to avoid the numb skulls who are eating pies, playing the ukulele, applying make-up etc in the comfort of their airconditioned armchairs as they make random attempts to kill me!!!!!!!

Offline chud

  • Full Member
  • *
  • Posts: 46
Re: Starter turning itself on and other electrical shenannigans
« Reply #3 on: July 07, 2008, 10:46:43 AM »
Thanks for the tip.  I'll disconnect those starter button wires.  But I'm still wondering why the red/white wire got burned. 

Just to clarify: my starter has turned over in the past.  It just never is able to get the bike running so I don't use it.

Offline Hush

  • Finally they realise that I am an
  • Really Old Timer ...
  • *******
  • Posts: 6,761
  • "Lady, I've heard it all before"!
Re: Starter turning itself on and other electrical shenannigans
« Reply #4 on: July 07, 2008, 11:06:57 AM »
The electrical drag from the starter motor might be enough to cause the burning, not sure but throwing the starter motor into the main motor when it is running would probably be something you don't want to do anyway.
I think the thing I most like about motorcycling is the speed at which my brain must process information at to avoid the numb skulls who are eating pies, playing the ukulele, applying make-up etc in the comfort of their airconditioned armchairs as they make random attempts to kill me!!!!!!!

Offline TwoTired

  • Really Old Timer ...
  • *******
  • Posts: 21,802
Re: Starter turning itself on and other electrical shenannigans
« Reply #5 on: July 07, 2008, 01:06:21 PM »
After looking through my wiring some more it looks like the red/white wire is the one that really got burned, all the way from the rectifier on up as far as I can see without tearing things apart too much. 

Can anybody tell me what's going on?  Rectifier bad or something else?  Thanks alot.

Check the green wires to/from the rectifier, too.  Check the Green wire connection to the frame.  These will burn when the battery is reverse connected, the rectifier shorts out, and possibly when the battery is low on fluid and then revved past 3000 RPM for, say, 10 minutes duration.

The starter does NOT use the Red/White wire for power consumption.  That wire is for the alternator to supply power to the battery/bike harness.

I'd guess that the starter button switch plastic has disintegrated inside the bar control and the metal pieces inside are now floating about and making random contact with things it shouldn't, and sometimes that is the solenoid activation terminal.

Cheers,
Lloyd... (SOHC4 #11 Original Mail List)
72 500, 74 550, 75 550K, 75 550F, 76 550F, 77 550F X2, 78 550K, 77 750F X2, 78 750F, 79CX500, 85 700SC, GL1100

Those that learn from history are doomed to repeat it by those that don't learn from history.

Offline chud

  • Full Member
  • *
  • Posts: 46
Re: Starter turning itself on and other electrical shenannigans
« Reply #6 on: July 12, 2008, 01:54:28 PM »
Thanks for the replies.  The green wire and yellow wires to/from the rectifier are fine.  Just the red/white one is burned.  It's burned from the rectifier all the way to the starter solenoid.  I looked at the handlebar switch, but the red/yellow starter button wire is already disconnected and taped off, so the short must be happening close to the solenoid. 

I'm still confused about what's going on.  Do I need a new rectifer or can I replace the red/white wire and reuse the old one?   

Thanks again.

Offline TwoTired

  • Really Old Timer ...
  • *******
  • Posts: 21,802
Re: Starter turning itself on and other electrical shenannigans
« Reply #7 on: July 12, 2008, 03:18:54 PM »
The green wire and yellow wires to/from the rectifier are fine.  Just the red/white one is burned.  It's burned from the rectifier all the way to the starter solenoid.

I'm still confused about what's going on.  Do I need a new rectifer or can I replace the red/white wire and reuse the old one?   

Perhaps if the rectifier shorted to it's attachment lug/post on the frame, that might explain the single wire meltdown.  I'd run some tests on the rectifier, too see if the six diodes are still functioning, and not shorting to it's mount.

Cheers,
Lloyd... (SOHC4 #11 Original Mail List)
72 500, 74 550, 75 550K, 75 550F, 76 550F, 77 550F X2, 78 550K, 77 750F X2, 78 750F, 79CX500, 85 700SC, GL1100

Those that learn from history are doomed to repeat it by those that don't learn from history.