Hello, new guy here but not new to riding - been riding 34 years.

Quick intro: Eleven years ago, I bought a complete basket case and built a "new" 1972 FLH. All that was usable was the frame, engine and the tranny. Everything else is brand new, including replacing the 4-speed sieve of a tranny with a new 5 in a 4 speed case after putting my foot down in an oil puddle and nearly dumping the bike. Now I have a leak-free bike, well…except if it's been a while since I've started it and the check ball gets stuck and it vomits oil all over the place.

Anyway, all the wiring is new too and has been working great since I built it. Around four years ago I replaced the stator and rotor.

I noticed today, the bike lights will blink off for a second about every 15 to 20 seconds. It does this whether the bike is in motion or not, idle or under throttle, high beam or low, even headlight on or off (taillight does it too). It is not vibration-related.

Tonight, when I went to start it, before I could even hit the starter button (engine too cold and me too lazy to kick it over) I heard a click that seemed to come from under the dash and the light went out for second.

It's been a long time since I wired the bike with a new, stock replacement wiring harness. Do these have a circuit breaker? It sure sounds like it to me.

What might cause it to be resetting? The only thing I've done to the bike recently is replace the wet-cell battery with a sealed unit. Only a few wires running to the battery so I know I didn't forget to connect anything.

Any clues as to where to begin looking? I know it must be something simple since the whole electrical system is so basic, but any thoughts on where to begin looking would be most appreciated.

Thanks

 

Yes there is a circuit breaker.(little black box.) Some even have a little silver box right off the pos. terminal.Wire runs from pos. terminal to breaker, then to starter solenoid .I assume since you turn the ign. switch on and the lights come on,you have a newer style switch.The old style, you had to click it one more time for the lights.Check all wires on ign. switch,make sure they are snug and not arching together.Nice looking ride.......

 

you have a short in the system some place = remove the dash turn the key back on see if it stops - keep going to the ignition switch remove a single wire just one and check by turning the ignition back on again than off - you will narrow it down than look at the wire diagram and see what it is - could be something like the front brake switch wire is grounded to the handlebar kind of thing in the switch box on the bars

 

"remove the dash turn the key back on see if it stops" ... Yep, This is where I'd go first ... Seen problems here MANY times

 

The breakers DO wear out. Take the dash off, and take an amp reading on the load side of the breaker. I'm not sure on the amp rating, I'm thinking 20 amps, if it's over that, it's excessive load. If not, it's a weak breaker and needs replacing.

 

Here`s my take on this…

You could have a bare spot in the wire that is in constant contact with ground. However, if this were the case, the headlights would not be lit at all.

You could have a bare spot in the wire that is intermittently coming into contact with ground, in which case the lights would work intermittently.

But it seems like your lights are going on and off in a pretty consistent manner, which makes me suspect a bad circuit breaker.

 

Wow. Great responses and helpful insight. I think I'm going to like it here!

I'll follow up when I have a chance to track down the problem.

 

Good, sound advise.
Very nice lookin' FL.

 

the beach bars and PM brake look good, too

 

My chopper did that to me too. The lights were working fine then I moved the clutch/switch housing. Turns out one of the wire terminals on the hi/lo switch was touching the handlebar and shorting. Prior to moving it the terminal was over the hole for the wires to go thru the bars. A direct short will cycle the lights and circuit breaker. Check all the wires and switches. Joe