Headlight keeps blowing

[Soloratov]

I'm planning on investigating with a voltmeter, but I figured I might get some opinions on what to look for. I have gone through 3 replacement bulbs in the last 2 months. It's just the low beam filament that is blowing, high beam seems fine. What is driving me nuts is it seems like a random time frame between changing the bulb, and the filament burning out. I have looked for a short inside the bucket, but didn't see anything before. I'll check again, but wasn't sure if there could be some low beam specific surge I could be encountering. Any ideas?

[Slack]

Just to make sure. . .
You aren't touching the bulbs with your bare hands are you?  If so the oils your skin leaves behind will cause hot spots on the bulb and it will prematurely fail.

[Soloratov]

Nope. I make sure I always use a clean napkin or tissue to hold it. The last two actually had a plastic cup you use to hold it with...kinda useful.

[fetor56]

Have all the replacement bulbs been the same brand....if they have then perhaps time for a change.

[Janx101]

Make sure the spring holding the bulb in is 'springing' ? .... Ie holding the bulb tight in its slot... Vibration while hot wreaks havoc on filaments.... And the GS has plenty of standard vibration! ... You don't need to add extra with looseness eh 

[Soloratov]

Hmm, I'll check the mounting. Never really thought about how tight it was.

The first 2 bulbs were the same, 3rd is different. What brands they were I don't know off hand, I just know I brought the 2nd to the shop and asked for something different.

[adidasguy]

Headlight blowing is a bad voltage regulator. Seen it a few times. Too high a voltage will blow the bulb.

Check with a meter. Voltage probably going over 18 volts. That blows the headlight really fast.

[fetor56]

The GS only has a basic type of electrical system so it's quite possible there is a large voltage fluctuation in your system.Since low beam is on almost constantly it bears the brunt of any fluctuation.A voltmeter would help & their not very expensive thesedays.
With my GS i can rev it with low beam on & the intesity fluctuates moderately.
NO WAY does this happen with my Yamaha TDM900, but extremely noticeable with my Honda 185S.
Contact a Motorcycle electrician over the phone & he'll give u free advice.

[Soloratov]

Ok, I'll check the regulator first...be nice if it was that easy. At least the high beam works, so that will get me around until I can track down this power surge.

[adidasguy]

High beam will blow out soon.
Never had headlights blow in succession except when the voltage regulator was bad. In fact, that is a good sign the regulator went bad. I have been there and seen it enough to know.

[Soloratov]

Hey Adidas. So I checked the regulator, it checks out perfectly. Took it to the bike shop, they gave it a quick test as well. No issues. I check wiring, everything is solid and resistance is zero. So I start getting a bit confused, and I am taking out this bulb and notice...this one isn't blown. Both filaments are intact. About to go into full WTF mode, I look down at the plug in my hand and notice the positive terminal inside it, is all bent and weird, like someone in the past had shoved a screw driver in there. When I was testing it, i never thought to actually look at it. Sure enough, I bend the thing back into shape...lights right up! SON OF A.....so, while it may work, i will just replace the plug. Must be bouncing down the road made the connection intermittent and it killed the cheaper bulbs.