Topic: Electrical Power (and engine) Intermittent Shut Down

[kennydean2000]

I have a 1974 CB750 K4 with about 18K on it.  Recently the entire bike will intermittently stall, electrical cuts out, motor stops, and I'm coasting.  Indicator lights go out, headlight, running lights, all quit.

I pull over, toggle some switches, play with the ignition and eventually it starts right back up.  This happens about once every 20 miles or so, it's not too predictable though.

I did recently install a Windjammer fairing.  I created a new wiring harness and followed instructions prior to this problem occurring.  Today I took it totally apart, built a new wiring harness, and I get the same behavior.  The electrics in the fairing work fine.

So - would a loose ground wire cause something like this?  I could have weakened something like that however I would not expect the entire system including engine to die - or should I?

Since it is intermittent it should not be a fuse issue.  The battery seems to be strong.  The electric start spins it up well every time - one the power is back on.

Any ideas?  I'm worried about this happening where it I can't get it going by simply toggling switches and I'm stuck.

Is there a main power circuit that would shut the entire thing down?  The ignition looks solid and I've not heard of this being a weak point in the system.   Thanks in advance for the advice.

[steam-powered man]

happened to me once, total shutdown.  quickly found the ignition switch base had become loose.  if this happens again, turn the key on and wiggle the switch base.  you may see the inst cluster wink on/off.  rebuild kits still available.  good luck,
bobp   

[Brian G]

I had a similar problem with my CB550K which appears to have been solved with a new fuse holder assembly. The original had an 'iffy' connection at the main 15 amp fuse and I fitted a used one from flea-bay (9 bucks) which so far has solved the problem. Not being sure, I also bought a replacement ignition switch; if the electrics conk out with the new fuse holder, the switch will be replaced next. From the sound of your problem -

I pull over, toggle some switches, play with the ignition and eventually it starts right back up.

I'd suspect your switch first.

Hth,
Brian

[taxiscooter]

Stopped one time 2 blocks from my house for a brew on the way home. Went out to start bike to go home , and it was completely dead ..... everything!  Gave up and pushed it the 2 blocks home. When I got home, I went to lock the forks and pull the key, and everything came back on when I turned the handlebars toward the lock position (key was still in the on position). The plug in at the back of the ignition had worked loose. I put a pull tie around the ignition and have had no further problems with it.

[750goes]

Had something similar on mine a few weeks ago, I had been forced to modify my ignition wiring by the previous owner having cut and joined many different wires for some reason. I now only run Positive Red into switch and Black switched power out of the switch.
The black wire was worn through in a spot I did not see, and rubbed against the head stem every time I turned right, it was hard to fathom, but I found where it was arcing. bit of heat shrink over the offending wire - all happy.


check you switch..

[kennydean2000]

Great input.  The fairing mount may have worked the ignition switch wires enough to create a problem.  I'll pull off the tank this AM and take a look.  Makes sense since it is the connection that can shut everything down.  If not I'll work back to the fuses.

Really appreciate it -

[kennydean2000]

Just an FYI to anyone interested, looks like the ignition switch.  Looked it over this AM, looked fine, rode it - same issues but getting worse.  The detentes in the switch are not lining up with the switch position.  Result was I limped it home with the key between the on and third positions.

Someone mentioned rebuild kits for the ignition - is this the best way to go.  Any ideas to get it going for tomorrow (Labor Day).  Running out of season and I'd like to get another day of riding in.  I'd rather not destroy the switch if possible.

Thanks

[steam-powered man]

when mine acted up on a ride, i temporilily held my switch halves together with a bandana to get home.  "fix" was 2 zip ties.  partsnmore has 'em,
bobp