Burning out the Headlight Low Beam

[Guest]

Nice garage-kept '83 GS850L, with about 9k. I've had it for a little over a month, and just burned out the headlight tonight - for the second time. Is it a fluke, or do I possibly have an electrical problem? It was cold the first time it happened, maybe 20s, but it was about 45 tonight. Both times it burned out at or shortly after I turned the key on/started it up.

Thanks for any ideas.

Mike

[Planecrazy]

I use my high beams exclusively during the day (better visibility to other drivers), and run my lows at night. Try running your high beams and see if the same thing happens. If it does, you may have a vibration problem rather than an electrical issue. The high beam, after all, uses a different wire for power.

If the high beam doesn't fry prematurely, maybe there IS something going on with the low beam wire ... or it COULD just be a fluke.

Let us know how it goes ... Good Luck!

Steve 8)

[focus frenzy]

first, do not touch the glass, the oils from your skin causes hot spots and the bulb will burn out very quick.

I could be a fluke, people often drop the package the bulb is in and put that one back on the display, the shock damages the filliment and they quickly burn out.

also charging system issues (over charging) will cause a bike to eat bulbs.

[JMHJ]

Low Beam, Etc.

Thanks for the info. I do have a strange vibration or buzz that occurs only at a certain rpm or speed, if I let the rpms get high enough as I shift through the gears. In 5th, the corresponding speed is 56-7mph (rpm unknown - the tach is unreliable, very sluggish). It's not too bothersome, if I just stay away from that speed. I may make another post about that at some point, if I don't find out what it is.

I was careful not to touch the bulb when I installed it, but I think I did drop the package at one point. I hope that's it. I'll shell out another $10 and try it again.

Mike

[Mike_H]

Ihad a similar thing happen, though I was popping fuses. First time it happened, I thought it was the headlight, but found the next day that it was one of the 10 Amp fuses under the seat, cheap fix. About a month later, same thing happens, I check the fuse, and it is no longer. Bummer. I don't mind one fuse, but two is starting to concern me. Well, after a close inspection, I found that the seat tab holding the front of the seat down had broken off, and was grounding the fusebox...I think. Removed the tab, and haven't blown any more fuses, but I am going to throughly check the charging system this winter.

[JT]

My 83 GS750 vibrates at the exact same speed. That'll probably be harder to trace and fix than what's causing your headlight issue. Check your wires going into the headlight connector and trace them back and make sure there are no issues. Then check how many volts are passing through at the battery and on some of your wires while the bike is running. If the voltage to your battery is high while the bike is running, you may need a reg/rect.

[Redman]

Maybe related to excessive vibration, but I would suggest the same as others have: Get a volt meter, Check battery/charging voltage. If too high voltagew it will burn out bulbs. Should be something like 13.5 to 14.0. If much over 14.5 then is probelm with charging system, either the R/R itself or the grounding of the R/R.

[JMHJ]

Thanks for the add'l info. Sounds like something I need to check.

[Doctor Shifty]

Check your voltage output with the headlights off, then with the lights on.

The stator has three windings, but only one of them is connected into the charging circuit when the lights are off. When you hit the light switch there is another contact in the switch that bridges windings two and three into action. This produces more power to run your lights and charge your battery.

The reason for doing it this way is to control the power output. The headlight burns up some of the extra power so that when your battery is charged up and not drawing much voltage from the stator, that voltage produced has somewhere to go. The regulator/rectifier unit is not robust enough to handle the extra voltage by itself as it has to turn it into heat and dissapate it.

Now that we've got this far ... the reason I've gone into the explanation like this is to say the following. If your R/R unit has a problem in controlling the voltage when the headlight switch turns those extra windings on, then the headlight will be getting a voltage hit that it can't handle and the globe will blow.

This is only one possibility along with the other suggestions about greasy fingers, etc.

And the "absolute with no exeptions ever for anybody at any time in GS history and that means you hiding back there behind that guy in the third row" cure-all for GS electrical problems is to check that every contact and connector on the bike is clean and functional. This is especially important for earth connectors.

Hope you get it sorted. My first bike in 1967, a BSA Bantam, used to blow the light if I revved too hard at night. It had a completely unregulated electrical system so night riding had to be very sedate.

Kim

[JMHJ]

Thanks. Sounds like replacing my Reg/Rect. unit might be wise? Not too expensive or difficult I hope.

[Redman]

Sounds like replacing my Reg/Rect. unit might be wise?

Well, no, not suggesting that. People have suggested to first check to see if the charging system is in fact overcharging. Do this by taking a voltage reading with bike running at mid RPMs.

If it is overcharging, then will need to determine if R/R is bad or if bad ground connection.

Suzuki R/R not cheap at all. Neither is aftermarket R/R. Can search the forum and find recomendations for less expensive other brands . . . . . . but at the moment dont know what your problem is.[/code]

[AOD]

Ihad a similar thing happen, though I was popping fuses. First time it happened, I thought it was the headlight, but found the next day that it was one of the 10 Amp fuses under the seat, cheap fix. About a month later, same thing happens, I check the fuse, and it is no longer. Bummer. I don't mind one fuse, but two is starting to concern me.

I had a similar issue on my bike that turned out to be a dirty / corroded fuse holder. The metal contacts on the fuse area get corroded, increasing the resistance of the circuit, making the fuse get too hot and melt.

I spent 20 minutes cleaning the terminals with contact cleaner and a wire brush and it's been great since. No one probably cleaned them in the prior 20 years.

~Adam

[Doctor Shifty]

Thanks. Sounds like replacing my Reg/Rect. unit might be wise? Not too expensive or difficult I hope.

Don't replace anything yet, just check the wiring connectors, and the voltage output etc. One of the common indicators of a failed R/R unit is the battery boiling itself dry with the amount of voltage it is trying to handle.

Look up the info on "The Stator Pages" on this site before you do anything with money.

If you do have to replace the R/R only do it after checking what other brands will do the job, such as (I think) old Honda 450 models, or the Electrex unit which is pretty bulletproof. All the info you need is around here somewhere, as well as several people who have already had to do the same thing.

Welcome to the wonderful world of GS electrics. :?

Kim

[tfb]

Yes, check all the connectors first, because (i) it's simple to do, (ii) it's cheap, and (iii) no point spending mega-bucks on stuff when all you've got is a dodgy connector. After a couple of decades or more, the connectors have attracted so much dust, oil and crud that you're bound to have problems with one sooner or later.

For peace of mind I have removed most of the connectors in my bike's 24-year-old circuitry, and have soldered the joints and put heat-shrink sleeving over them. Things are much more reliable now.

Mike.

[Jackrp]

Re: Burning out the Headlight Low Beam

[quote="JMHJ"]Nice garage-kept '83 GS850L, with about 9k. I've had it for a little over a month, and just burned out the headlight tonight - for the second time. Is it a fluke, or do I possibly have an electrical problem? It was cold the first time it happened, maybe 20s, but it was about 45 tonight. Both times it burned out at or shortly after I turned the key on/started it up.

Thanks for any idea
My 850 was blowing thru bulbs once, turned out the headlite bucket to ears bolts were loose, Check those 2 bolts