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Discussion Starter #1
came back from a 80 degree 300 mile ride on my Road Star Monday night, only to get on it last night to find the headlight was not on. I replaced the fuse and popped again

Today I've removed the seat, gas tank and moved all wires to free them up and tried ignition, lights come on over and over with ignition turned on etc until none actually starts at which headlight simply goes off.

Blinkers work perfect and bike starts and runs fine, just no headlight

Any thoughts
 

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Did you check the voltage? The headlight is a large load, and if the regulator went bad, and it's putting out like 18v, it's likely to blow a fuse with the increased amp load.

Only thing I can think of, other than a short somewhere.
 

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Discussion Starter #3
Did you check the voltage? The headlight is a large load, and if the regulator went bad, and it's putting out like 18v, it's likely to blow a fuse with the increased amp load.

Only thing I can think of, other than a short somewhere.
What's the best way to check the voltage ? I have a circuit tester

I was going to remove head light and check connectors as well
 

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To check voltage regulator :

 

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Set your meter like this. A fully charged batterewill head 12.45.

 

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Engine off, headlight on, light worked, correct?

Started bike, headlight blew out, correct?
 

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Discussion Starter #8
Engine off, headlight on, light worked, correct?

Started bike, headlight blew out, correct?
Yes, I can turn key on several times with me flickering on and off switch, high beams and turn signals and its fine until I start bike and then the fuse pops
 

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What is voltage above 2000 rpm, revving engine pretty good ?
 

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Discussion Starter #11 (Edited)
Headlight still removed from bike

Looking through wire inside housing and nothing sticks out there

Nothing aftermarket and only removed tank about two weeks ago to work on fuel gauge but ride daily practically and headlight has always worked so am guessing it happened on Mondays trip as it was day time and maybe I just didn't notice it
 

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Your voltage regulator specs good. You have an electrical short in the headlight wiring somewhere. I'm heading to bed and off tomorrow, I'll look at the wiring diagram to see if I can fiquire something out.
 

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Discussion Starter #13
Your voltage regulator specs good. You have an electrical short in the headlight wiring somewhere. I'm heading to bed and off tomorrow, I'll look at the wiring diagram to see if I can fiquire something out.
Thanks, enjoy your rest and day off - much appreciated
 

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Seems odd, if I read that right, it doesn't blow the fuse if the bulb is removed?

The only thing that should be doing is disconnecting the ground from the bulb, as the power sides should still be powered, unless something is bad with the bulb itself.

https://www.weeksmotorcycle.com/roadstar_wiring_diagram.html

From that diagram atleast, it says the only things are the headlight, indictator lights (high and key on) and the starter switch.

Does the headlight work when it's off? and the indicator lights? sounds like we can ignore them if that is the case, and only look at the starter switch and relay.

I would guess the starter relay is drawing too much current then. Maybe start the bike without the headlight bulb conected, then after the bike is running, connect it, and if it is fine, I would look at that starter relay drawing too much current.
 

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Discussion Starter #15
Seems odd, if I read that right, it doesn't blow the fuse if the bulb is removed?

The only thing that should be doing is disconnecting the ground from the bulb, as the power sides should still be powered, unless something is bad with the bulb itself. 4th

https://www.weeksmotorcycle.com/roadstar_wiring_diagram.html

From that diagram atleast, it says the only things are the headlight, indictator lights (high and key on) and the starter switch.

Does the headlight work when it's off? and the indicator lights? sounds like we can ignore them if that is the case, and only look at the starter switch and relay.

I would guess the starter relay is drawing too much current then. Maybe start the bike without the headlight bulb conected, then after the bike is running, connect it, and if it is fine, I would look at that starter relay drawing too much current.
No Sir, it still blows the fuse without the head light connected and only when it is running

So I can hit the start over and over, still good - once the bike starts running it kills fuse instantly
 

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Discussion Starter #16
and it's only the head light fuse, the fuse seems to only run the headlight as blinkers and everything else is fine

Without a fuse bike runs fine with everything else working
 

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Discussion Starter #17
Just had a thought, on my bike the lights below only come on when bike is actually running ( not sure if this is normal or the way the previous owner ran them )- this could be the reasoning behind it only blowing when bike is running

In theory, if the broken wire is running to them and it's only hot once running that means all the other times the short isn't being met until its actually running which is the reasoning behind the fuse popping


Thoughts?
 

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that makes sense. The passing lights on my royal star have a lot of wires passing thru the bend where the light attaches to the cross holder for the pair

if one of those wires is shorting, or if for some reason one of the bulbs itself is shorting, that would blow the fuse when the lights turn on... ...
 

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You have approx 120watts to work with, lets just assume 100watts is the max, to give the fuse alittle safety room.

If the headlight is 55w low and 65w high (I think the bike normally calls for a 35 or 45w, but autostores only really stock 55w ones).
I'm not sure what your passing lamps are, seems your bike is different from the schematic I found, likely different year and they made changes.

I see passing lamps anywhere from 30 to 50w, so if you have 50w passing and 55w headlight, that is a total of 155w and it should blow that fuse easily.
If you have the normal 30-35w passing lamps, it would be 125w and it will blow, but might take a few seconds.

What year is that bike, and check the wattage on the bulbs. It doesn't sound like a short at all if removing a bulb causes it not to blow, has to be overloaded.

Oh, I'm assuming it's a 10amp fuse, what size fuse is in it?
 

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the thread is getting confused...

AW posted a bit back: ...No Sir, it still blows the fuse without the head light connected and only when it is running...

need to get an ohm meter on the headlight side of the fuse, and isolate the short to the chassis.
 
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