Topic: Flickering headlight... Bad switch?

[DaveI]

I just recently finished fixing some charging issues on my cb750 k4. I pulled out the multi-meter and saw I was getting higher than spec voltages at the prescribed rpms but also noticed the headlight flickering on and off after a few mins before the fuse blew.

When the headlight fuse blew the whole bike died.. Not sure why but I threw a 15amp fuse in to check it, re-adjusted the voltage regulator to spec and it was still happening. Could this be the switch shorting or something else going wrong.
I have a brand new aftermarket wire harness if that helps. And does anyone know why the headlight fuse blowing but not the main kill the whole bike?

[harisuluv]

I don't know if this helps but I was fixing a cb550 that I was flipping recently and the starter switch broke while I was doing diagnostics/getting it running.  Put it all back together and just figured I would use the kick starter.  Later noticed that the headlight wouldn't come on, pulled it apart and everything seemed fine and plugged in.  Came on here and did a quick search and found some people saying that the headlight circuit goes through the start switch.  With that circuit disconnected the headlight was getting no power.  It's late and I am already forgetting exactly your problem but I hope that helps.

[Lamp]

I have a K2 750, and there's only one fuse on the entire bike. I'd bet your voltage regulator is dying in the slow dramatic fashion they do. The headlight issue may be unrelated. Probably just a loose connection. Went through a similar issue with my bike. I kept blowing fuses, so I just kept upping the amps of the fuse, until I blew out every light but the headlight lol.

[trueblue]

If the diodes in your rectifier are leaking, ie, letting current flow in both directions, you'll get a flickering headlight, and possibly blow fuses.

[lucky]

First take the headlight off and hook it direct to a battery. Does it flicker?

[DaveI]

The headlight doesn't flicker on battery power or when I turn the headlight switch on. It only flickers when the headlight switch is turned off. I thought maybe the switch was freakin out or making contact with the vibrations of the bike.
I don't know if this is unrelated but when I turned the bike I to check it no oil pressure light today. These electrical gremlins are getting under my skin now

[DaveI]

I have a K2 750, and there's only one fuse on the entire bike. I'd bet your voltage regulator is dying in the slow dramatic fashion they do. The headlight issue may be unrelated. Probably just a loose connection. Went through a similar issue with my bike. I kept blowing fuses, so I just kept upping the amps of the fuse, until I blew out every light but the headlight lol.

I like your style.  I am up to a 20amp in the headlight just to get it back home.  Can't be good.  But a new regulator and a new rectifier are on order from Oregon.  I emailed Tony and he seems to be very knowledgeable.  Hopefully this will fix the gremlins