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#588981 03/06/15 11:30 pm
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69 Bonnie......headlight bulbs are having a short life.
Bike still has original Zener and rectifier.
Poor bulb manufacture? Any ideas?

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Yes , plenty of ideas , some even valid .

Vibration is a killer , it could be as simple as this .

Have you checked the max dc voltage
to see if and when that the zenner is cutting in ... and doing its job ?

I would recommend a more modern rectifier/regulator (generic black box )
, but this would answer a different question
you did not ask .

.

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Check the ground connections of the zener. Take the bits off and clean up any oxidation. Poor connections here can give voltage spikes. Look for any wires that have frayed and holding by a couple of strands. Check battery terminals, grounds and fuse holder. Dismantle and properly clean them.

What are you using for bulbs? brand name, etc? Have they blown while riding with lights on or have you first discovered the problem when you go to use the lights?

Examine the filaments. Does it look like they've melted/fused? Or do they look more like a fracture?

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My first headlamp bulb blew in a couple of weeks, it was an expensive high end type.
I replaced it with a cheaper type which still does the job and it's lasted two and a half years so far.

The reason?... cheaper bulb filaments contain less tungsten and so are less brittle.

davy

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On my T100 road bike, almost every nut and bolt has rubber washers or o rings, including the headlight mounts. Bulbs last a long time. If your blown bulb is white and milky inside it usually indicates an air leak which equals a duff bulb. Ridden many a mile with the lights on and the rubber o rings/washers seem to make the difference. No cracks in the fenders or anywhere, nothing falling off and good lamp life. Cheers, Wilf


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Hi,

Originally Posted by SEATTLE GS
69 Bonnie

As well the others, if the headlamp is the original British Pre Focus:-

. Do the cap and spring hold the bulb tightly in the reflector?

. Does the cap have a loop attached?

. If it does, does the loop have the original push-in bullet terminal, with a wedge-shaped cut-out? If it does, the Red return cable conductor is just folded up and pushed into the terminal; at least, you need to pull all this apart and ensure it's all clean and tight; otoh, ime and mho, the bullet is best replaced with one like those that fit in the snap connectors.

. If the cap doesn't have a return cable attached, the return for the bulb is currently through its contact with the reflector, the reflector's contact with the rim, the rim's contact with the shell and a Red cable to a loop rivetted into the bottom of the shell. Apart from that was always a crap electrical return path, the shell cable loop is rivetted just where any water collects and rusts the shell, so it's now an even worse return path ...

The headlamp needs a good direct electrical return path, at least into the Red cables network in the harness.

With a meter, you should be able to measure zero-Ohms continuity:-

. from the headlamp bulb to the Red cables' connection around the head - head-steady or head/rocker box bolt/stud;

. from that engine Red cables' connection to battery +ve.

You should also check the wiring stuffed into the headlamp shell, to ensure that, when the headlamp's in there as well, nothing's being badly-crushed and/or -bent.

Hth.

Regards,

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THanks, I will get my hands on the bike next week and check. I had it last year and cleaned up all the grounds and connections. I would like to replace the reg/rect with a blackbox, I was wondering if it might allow a sudden spike and blow the bulb. I just spent some time tracking down a short that was blowing fuses intermittently. Now on to this bug. I will double check the Zener and its ground, usually a bear to get to.

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How high are you revving the engine before shifting?
This sometimes is a cause.

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Clues:
Is there a piece of a broken filament floating around inside the glass globe?

Is the filament vaporized and the end of the support wires melted into a small ball from heat?

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The bulb has exploded the filament...there is a white haze in the inside of the bulb...I think I can rule out vibration. I will check out all the grounds and connections tomorrow. How about throwing in a black box reg/rect to eliminate variables.?

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I was going through a bulb a week in the tail light until I got rid of the stock grounding system and made my own. Same for the head light.
Electronic regulator is only plus. People who cling to stock regulators/rectifiers and ignitions baffle me. It's like cooking the rear chain in a skillet full of grease on the stove. It's in the book but the book is 40 years old.


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Hi,

Originally Posted by SEATTLE GS
The bulb has exploded the filament...there is a white haze in the inside of the bulb...I think I can rule out vibration.

Why? Aiui, "white haze" indicates an air leak into the glass envelope. Also, the filament has "exploded"(?). What would induce either of those except vibration?

Originally Posted by SEATTLE GS
I will check out all the grounds and connections tomorrow.

Bear in mind that the headlamp shouldn't use "grounds"; you should be able to see a cable all the way from at least very near the headlamp bulb to battery +ve.

Originally Posted by SEATTLE GS
How about throwing in a black box reg/rect to eliminate variables?

"variables"? confused From your posts, the problem is only with the headlamp bulb?

Hth.

Regards,

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Don't skimp on bulbs for your bike. There are some horrible ones out there. I've had them disintegrate in my hand before I've even installed them.

I have one of the original halogen kits in my Norton from the '80's. It still has the original bulb in it. It cost me 35$ back then, but it has appeared to have been worth it.

If you prefer to run filament bulbs, be sure to check the bulb that comes out. Vibration will erode the two soft contacts and that means you should probably use rubber mounts.

A motorcycle by any anyone's criteria is a hostile environment for electrics of any kind.

One only has to have the lights go out on a fast corner in the dead of night to really appreciate the need for special attention to your electrics.


Cheers,
Bill


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Those little halogen riding light bulbs that go in the pilot position don't last long on my bike but the normal old fashioned pilot and headlamp bulbs last for years.

Dave

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I ran quartz halogen sealed beam units in a couple of my bikes. They last a year, maybe. But, they're 7.00$ at NAPA. I went back to filament type and they also last just one year, but are a couple bucks cheaper.

I think you just get what you pay for, for the most part.....


Cheers,
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I don't think I've ever blown a headlight (55/60 watt h4) or tail light. The little speedo and pilot bulbs go occasionally. I did try led's in those, but found them no better (in fact worse, as they are more expensive! )

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My 650 used to shake bulbs to bits.

Now have rubber mounted head and tail lights and bulbs last forever.


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The bike does not have any extreme vibration, but I won't rule it out as a problem. I will make a ground from the headlight to the frame

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Make a ground from the headlight bulb to the battery. You'll be amazed at how bright the headlight can be.


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Here's something very simple to try, and it might fix your problem. Put a dab of general purpose grease on the bulb's terminals before installing it.

Seems to work for me... snap, snap.

http://www.hermit.cc/tmc/technote/446bulb/index.htm


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check for AC current across battery terminal s


Bob, Lifetime bike: '71 T120R, bought in '71 at Ken Heanes, England.
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Hi Bob,

Originally Posted by btour
check for AC current across battery terminal s

Aiui, no; batteries supply, and are charged by, DC.

What you're possibly thinking of is John Healy's advice to check for AC leaking across the rectifier to the DC side? But, while AC won't do electronics any favours, incandescent bulbs shouldn't find it a problem? With the old 6V systems, the lighting was supplied by four of the alternator stator coils.

Hth.

Regards,

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hi h smile my problem was rectifer going intermittent. ac surges. i guess with no dc bank. it was the devil to figure out.


Bob, Lifetime bike: '71 T120R, bought in '71 at Ken Heanes, England.

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