Author Topic: Headlight bulb burning out quickly (Read 1360 times)

mitchell · « **on:** August 17, 2012, 03:16:37 PM »

Hi all. My headlight bulb blew last week and I finally found one locally but the low beam burns out the moment I switch on. The hi beam will burn out after about 10 seconds. So, I've gone through 2 new bulbs in less than a minute. With no bulb in place, the ammeter will just slightly go towards the negative when I turn on the switch. Does this mean the handlebar switch is bad?
All the wiring inside the case looks good, no broken or exposed wires. The harness and switch were brand new a year ago.
1972 bullet 350 standard.
Any thoughts?
And, something I noticed during my rides in India is that a halogen bulb burns out really fast too. Is halogen just too much for our systems to handle?

Thanks,
Mitchell

Bullet.wagon · « **Reply #1 on:** August 17, 2012, 03:28:46 PM »

I would check the voltage at the plug in. Maybe the voltage regulator is not funtioning causing higher than normal volts.

mikail gransee · « **Reply #2 on:** August 17, 2012, 04:40:50 PM »

I ordered some bulbs for my 500 and had same prob then checked them and found out they all were rated for a 6 volt system.

. I have a 12. Over charging could also be your prob specially on the "new" models that have a feed wire right from the stator.

mitchell · « **Reply #3 on:** August 18, 2012, 01:36:09 AM »

Mikail, all the bulbs are indeed 12 volt. So that is not the problem...if only it would be that easy!
BW, I will borrow a tester and see if the voltage is constant.
Just when you think all is working right, something else comes up to boggle the mind. We Enfield riders must be masochists, no?

barenekd · « **Reply #4 on:** August 18, 2012, 10:21:54 AM »

Don't forget to check the grounding, too. A bad ground can cause problems.
You might want to buy a Multimeter. You can get a decent one for $20.00. You will probably need it on a few occasions with an Enfield.
Bare

mrunderhill1975a · « **Reply #5 on:** August 19, 2012, 10:45:18 PM »

I had the same problem, it was the small voltage regulator under the seat.

mitchell · « **Reply #6 on:** August 21, 2012, 11:34:22 AM »

I have the 2 in 1 combo of the reg/rect .
I did have the 2 seperate. Is there any preference over which to use? ie, are 2 better than one?
Also, since my battery remains charged, could this problem be something other than the regulator? All other lights work fine too and the wiring all looks great everywhere.

mrunderhill1975a · « **Reply #7 on:** August 22, 2012, 12:31:21 AM »

Do you have a 3-wire alternator or a 4-wire alternator?

Chasfield · « **Reply #8 on:** August 22, 2012, 02:28:11 AM »

Yeah, if you have four wire alternator your headlamp bulb will be running off a separate regulated AC circuit, independent of the main 12 volt harness. So it can can have over volt faults even though everything else on the bike works fine.

mitchell · « **Reply #9 on:** August 23, 2012, 03:13:58 PM »

Took my bike to a local shop and they confirmed that it was the diode/s in the rectifier portion which was not functioning properly.
I pulled the old one off today and found that it was glued to the backside of the left tool box. No mounting screw used. Could this be a reason for it's short life span?
If it is, I am open to some ideas on where to mount the new one. I'm thinking it has to be bolted to the frame, no?

mikail gransee · « **Reply #10 on:** August 24, 2012, 03:26:27 PM »

I think it needs to be bolted for grounding reasons and in a open place to air cool it. GLUED...ha. ha. Talk about cutting corners.

mrunderhill1975a · « **Reply #11 on:** August 24, 2012, 07:58:59 PM »

That could be the problem, you could just buy a new rectifier from RE dealer or you could build one yourself using Radio Shack or Malpin bridge diode. I did this myself, the factory rectifier seems to be prone to failure in my experience, while the regulator is bullet proof. The Radio Shack or Malpin bridge diode has worked on my bike for seven or eight years now. Jim Downey pointed me in this direction and I quote: "A typical motorcycle alternator puts out about 8-10 amps. Radio Shack offers a full wave bridge rectifier* (part number 276-1185) that is rated at 25 amps and it will withstand up to 50 volts, much more than any bike will put out." See the attached photo. The photo makes the wiring look complicated but in reality it is quite simple to build. The two white and green wires with the yellow tags are the alternating current from alternator. The orange wire is the positive to the regulator and the battery. The black wire is the negative to the regulator and the battery. I used the heat sink from the old rectifier and attached the bridge diode with a bolt to ground.

mitchell · « **Reply #12 on:** August 29, 2012, 01:53:06 PM »

I bought a new combination one at a local shop. The reliable owner said it is heavy duty. I made a bracket to mount it on which will span under the seat using the two seat mount bolts for ground.
I will use a good-quality trailer light connector to hook up to the system.
I will find out tomorrow if it works.
Thanx all

mitchell · « **Reply #13 on:** August 30, 2012, 12:41:50 PM »

Well I replaced the reg/rect, added a mounting bracket, rewired, added a new bulb and...pop. Another bulb bites the dust.
The white flag is up.
I have done all I can do with my knowledge. I see no breaks in the line anywhere.
Any ideas greatly appreciated.
Thanx

Arizoni · « **Reply #14 on:** August 30, 2012, 01:40:14 PM »

Do you have a volt/ohm meter?
It would be interesting to see what the voltage reading is between the headlight wire and ground.

I'm not sure what to do with the reading but there might be someone here who would take a look at it and say, "Whoe! That's the old waveflux problem which is easily fixed by parking your bike headed North." or something like that.

mitchell · « **Reply #15 on:** August 31, 2012, 09:08:15 AM »

I do park facing East but...
I ran a wire direct from the ground 'sleeve'(where the orange wire slips in from the left handlebar control) and direct to the neg battery terminal. Same result. At idle, the bulb looks fine. When i increase the throttle, it burns out in a couple of seconds. Now I am out of bulbs. $40 in bulbs in a week. Is there a way to check it without risking another bulb???

mrunderhill1975a · « **Reply #16 on:** September 01, 2012, 12:44:23 AM »

You can test the circuit using a multimeter rather than using more bulbs.
Ok, we need to start at the beginning. 1)Do you have a 3 wire or a 4 wire alternator?
2) When you attach a multimeter to the headlight contacts, are you getting Alternating Current or Direct Current?
3) What is the voltage of the headlight connections with the engine at idle and what is it with the engine revving?
4) In addition to the "combination " regulator/rectifier you have installed, Is there a small black voltage regulator (approx 1"x 1"X 1.5")llocated somewhere (not the turn signal flasher and not metal regulator, but a separate regulator encased in black plastic)?

mitchell · « **Reply #17 on:** October 15, 2012, 01:14:26 PM »

So I finally got some time to get into it again. No luck. I brought it to a recommended mechanic who is a harley whiz. He spent some time for me looking over what work I had done and gave me a few things to look for yet again. But just before i was leaving, he moved a nest of wires around and says, 'what's this?'
I look in there and see a small a/c regulator with a burn hole in it. ! I mean mounted on the side of the rear mudguard and nestled just in from the toolbox 6" from where I had been working to install the new a/c voltage reg/rect and all the rewiring/soldering and remounting I had done. Like it had just manifested itself there. How could I have missed it?!
Because the bike kicks and runs with it unhooked, it appears to be a dedicated headlight regulator. I never knew the bikes had one.
The writing on the part says:SWISS AC REGULATOR 12 V. And on one side: SAP-816 Bullet Machismo DIESEL 09-06-2010.
So, I have a new on order from enfieldparts and should get it any day now.
Question: What might have caused it to blow, so I can avoid burning the new one ($40) and is mounting it on the mudguard an effective ground?
Thanks All,
Mitchell

mitchell · « **Reply #18 on:** November 01, 2012, 03:05:12 PM »

I replaced the headlight regulator, mounted it to an aluminum bracket and ran a new ground wire from the headlight socket to the connector, put in a new bulb and it works perfect!
Thanks to all for your help,
Mitchell

LarsBloodbeard · « **Reply #19 on:** November 01, 2012, 06:35:18 PM »

Quote from: mitchell on October 15, 2012, 01:14:26 PM

Question: What might have caused it to blow, so I can avoid burning the new one...

Glad you got it rectified.

To answer your question, many things could cause it to fail. But the only reason it would burn up like that is if it had an internal short or a component catastrophically failed. It could have been a manufacturing flaw. It could have been shorted between the external terminals. A voltage spike could have damaged an internal component. It may not have been sealed properly and water or something got into it. Etc.

mitchell · « **Reply #20 on:** November 03, 2012, 03:14:49 PM »

Thanks Lars. I am guessing/hoping that it was just a poor quality item and the new one will be better...for awhile. I also feel more confident that running a new ground wire avoids a relapse.
Mitchell

forrestt · « **Reply #21 on:** November 18, 2012, 07:37:56 PM »

This sound like the kind of thing that would happen to me. ...hope you got it sorted.

Menu

Members Rides

NField Gear

Author Topic: Headlight bulb burning out quickly (Read 1360 times)