Topic: Headlight low beam trouble

[Swede]

I have a 76 CB550 with a low beam problem.  When I bought the bike last fall the low beam was burnt out.  So I replaced the headlight and the other day I found that my low beam was burnt out again.  Since replacing the headlight I have only put about 100 miles on the bike.  I am starting to wonder if I am having some kind of wiring problem.  I don't really know where to start.  Any suggestions would be appreciated.
Thanks

[hcritz]

Hey Swede...
It's probably just a coincidence...or a bad bulb...
If it's a halogen bulb....it could be low voltage to the bulb...the halogen cycle that makes these bulbs work require proper voltage...I have heard that low voltage can cause early failure. Probably be a good idea to check all the connections involved and test the voltage at the bulb and see what you have.

[howardstapley]

Im with hcritz on this one but when you go to replace the bulb, check the wires for any clear sign of trouble, fraying, loose, burnt, that sort of thing.

[grumburg]

Used bulbs usually are 30+ yrs old and the low beam gets the most use. I went through 2 in one season (Stanley originals). Also, make sure the prongs fit tightly in the plastic plug that the headlight plugs in.

[csendker]

So, it is a standard incandescent or a halogen?  Got a meter?  What's the voltage at the headlight plug?  Cruddy connectors increase the resistance, decreasing the voltage.  Check the connectors throughout the lighting circuit, and clean them up.  And if they're all real cruddy, check the others too.  While low voltage isn't something a halogen would appreciate, it would only dim an incandescent - not blow it out.  Real bumpy roads will decrease the lifespan of the filament.  Excessive voltage would pop one also.  A short somewhere will wreak havoc.  Burned out switch too.  I'd start with the voltage, look for obvious shorts, clean up the connectors  and go from there.