[Royal Stargazer]

Last weekend while putting on as many miles as possible on my bike before the upcoming snow, I lost my headlight.

Saturday night, I noticed that my headlight was cutting out intermittently. I'm used to the bulb dimming at idle, and I'm used to the beam bouncing around as I hit the numerous imperfections on Minnesota roads, but this time it would actually cut out for a split second almost every bump I hit. I wrote it off initially, but Sunday morning, refreshed from a full night's sleep and eager to dial in my carb after the 535cc piston upgrade, I went for a ride and noticed my headlight was completely dark.

I did some searching, and found a few tales of bikes that had a problem blowing headlamps, but my standard 5-3/4" sealed beam doesn't show any signs of wear or damage. It simply won't light, high or low beam. The high beam indicator on the speedo doesn't light, either. I've broken out the multimeter and it appears as though there is power getting to the headlight, which leads me to believe the bulb is toast, but wouldn't I see burnt filaments or other damage? 

I don't suppose anyone has seen this sort of behavior before, and might be able to point me in the right direction?  The bike is a 2003 Bullet 500 ES, four wire alternator. I've replaced a couple bulbs here and there - a tail light and a couple speedo bulbs - but the electrical system hasn't otherwise behaved in a way that led me to believe there might be a problem. The primary case has fresh type F, and the battery is about a year old, and still strong.

[tooseevee]

Last weekend while putting on as many miles as possible on my bike before the upcoming snow, I lost my headlight.

Saturday night, I noticed that my headlight was cutting out intermittently. I'm used to the bulb dimming at idle, and I'm used to the beam bouncing around as I hit the numerous imperfections on Minnesota roads, but this time it would actually cut out for a split second almost every bump I hit. I wrote it off initially, but Sunday morning, refreshed from a full night's sleep and eager to dial in my carb after the 535cc piston upgrade, I went for a ride and noticed my headlight was completely dark.

I did some searching, and found a few tales of bikes that had a problem blowing headlamps, but my standard 5-3/4" sealed beam doesn't show any signs of wear or damage. It simply won't light, high or low beam. The high beam indicator on the speedo doesn't light, either. I've broken out the multimeter and it appears as though there is power getting to the headlight, which leads me to believe the bulb is toast, but wouldn't I see burnt filaments or other damage? 

I don't suppose anyone has seen this sort of behavior before, and might be able to point me in the right direction?  The bike is a 2003 Bullet 500 ES, four wire alternator. I've replaced a couple bulbs here and there - a tail light and a couple speedo bulbs - but the electrical system hasn't otherwise behaved in a way that led me to believe there might be a problem. The primary case has fresh type F, and the battery is about a year old, and still strong.

         You don't always see any damage when the filaments on a sealed beam give up and surrender. You probably just beat them to death 

         Your easy way out is just go to an auto parts store (or Walmart) and buy a new sealed beam. They're very common, cheap.

[mrunderhill1975a]

It could be a few different things.  If you have a battery and some jumper wire, connect the jumpers to the back of the headlight and see if anything lights.  If it does, your problem is somewhere else.

On my bike the headlight would be on and off at random it seemed.  Then once while pulling into a dark garage, the light went out when I turned left. 

After following the leads from the nacelle through the wire bundle under the tank, and cutting the black tape around the wire bundle, I finally found a black wire that had broken after thousands of left turns.  So, If your bulb is not burned out, check the wire bundle where it rubs on the head set.
I see you have a 2003 Bullet ES,  Attached is a 2004 wire diagram  that could help?

[Tarnand]

If, like you mentioned, the high beam indicator on the speedo doesn't light, it most likely mean that the current from alternator does not get to bulb in your head light.  I would start by making sure that both butt end connectors for  YELLOW and AMBER wires that are coming from the alternator connect to the main wire harness. 

These connectors ale VERY lousy and they actually MAY disconnect due to vibrations or corrosion. They are somewhere under the air box and by simply pulling the alternator cable you can get them into the open.  That at least how it works on my 2005 Bullet.  If the cables are too short then just remove the air box and you should be able to access them there.  There will actually be 4 wires in that cable - besides already mentioned YELLOW and AMBER there will be also 2 VIOLET wires that are providing power for DC regulator but I understand this is not a problem.

Another possibility, but I can't really tell if it actually could be the culprit, is failure of your  AC voltage regulator.  On my Heritage I once fried my battery and burned the head bulb just because I did not realized that my regulator went bad.  In case of Bullet I do not think it would hurt the battery but burning the headlight and the indicator is a likely possibility. 

The last one was already discussed by mrunderhill1975a

Good luck.

[Tarnand]

These are the connectors I was talking about.  The weather got warmer so just today I started rewiring the whole harness.

[Royal Stargazer]

Now that I have access to my computer on the very last nice day before winter storm BS hits, I've found the problem: the AC regulator took a crap.

The bulb is good, and the alternator is still rocking (thank goodness,) but that AC regulator is toast.

My dealer didn't have any on hand, so barring eBay, does anyone have any leads on an easily-sourced substitute? I seem to be coming up empty handed, save for online vendors.

Thanks, all!

[Royal Stargazer]

Okay, it turns out I'm an idiot. I have VIVID memories of testing the amber and yellow wires at the alternator, but I just went out there and checked them again, and they're not putting out any juice.

Alternator time for me, I suppose.

[mrunderhill1975a]

Search the internet for "Trail Tech Universal Voltage AC Regulator - 7003-AC01 "

They are available from many sources (amazon etc) for about $15-$22. Perhaps even our host has a supply.

I put one on after repeated popping of Lucas vintage style headlight bulbs.  You can dial in the brightness , dim for long life and bright for shorter life.

My headlight has now lasted for years.

[mrunderhill1975a]

Ahhhh, the amber and yellow are not moving electrons.  Time to open the primary cover, see if you can find a break in the Amber-yellow coil on the stator.  Possibly, you may be able to re-solder if you can find the break in the circuit.

[Royal Stargazer]

I hadn't considered that. I was concerned that I would have to replace it entirely - that there was no coming back.

I had started to research rewiring the alternator to convert the headlight to DC, and removing the headlight jumper. That doesn't seem to be too uncommon a modification, though there seem to be a few different approaches to it.

Either way, I might as well get some gasket maker, and open the primary case... As soon as the snow melts, that is...

[Royal Stargazer]

Reckon an update would be in order.

Opened the primary case to see if anything fishy was going on in there, and found some bits of metal jammed up in the stator. They were pieces of the primary chain. Holy crap!

At least the job looks fairly straightforward. If I can get the parts this weekend, I'll be back on the road in no time, and maybe - just maybe - I'll have my carb dialed in before the snow files.

[mattsz]

Reckon an update would be in order.

Opened the primary case to see if anything fishy was going on in there, and found some bits of metal jammed up in the stator. They were pieces of the primary chain. Holy crap!

I'd say you're pretty lucky - that could have gone much worse...

[mrunderhill1975a]

Wow, that could have been much worse...put this thread in the community knowledge base.  Many things can cause headlight problems,  its just that this is one that would not have occurred to me.

[cyrusb]

Yikes, How many miles are on your '03?.

[Royal Stargazer]

Yeah, I'd say I lucked out... I couldn't find any other signs of damage in there, so thankfully only the alternator and chain need replacement. I ordered the parts, but my poor bike might be off the road until June!

The bike's only got a little over 5,000 miles on it. I'm wondering if maybe it's the age, not the mileage that would have contributed to the failure, or is there another factor I should be looking into?