headlight hiatus

[gr333nyboy]

hi,

any ideas about this (slightly?!) worrying thing that happened the other night?

i took my 79 gs750 out for a run in the dark (as i try to run it every day to keep it in best order) and i had just got back from the run, it was parked, engine still running, i went to open the garage door when the headlight suddenly went off! i thought it must have blown, but it then went back on without being touched, it must have been off maximum of 2 minutes, but this has everso slightly freaked me out about night riding now.

this must be a wiring problem mustn't it? something come loose? i have tried to replicate the fault by handling every wire i can see near the headlight while its on, but nothing, the lamp stays on fine now.

any ideas how i track down this fault to avoid the potential nightmare of my headlight going off on a dark road at speed?

thanks,

mark

[rustybronco]

i went to open the garage door when the headlight suddenly went off! i thought it must have blown, but it then went back on without being touched, it must have been off maximum of 2 minutes, but this has everso slightly freaked me out about night riding now.

this must be a wiring problem mustn't it? something come loose?

Not necessarily. If it still uses a sealed beam style head lamp, a loose filament inside it would do the same thing.

[gr333nyboy]

thanks rustybronco,
no, i don't think so, the headlight has a removable bulb, in fact a great yellow french-style light bulb i got in all the way from california.

[rustybronco]

Then most likely, you are looking for a bad connection or a bad headlight switch.

[gr333nyboy]

ok thanks for that.

[rustybronco]

Keep in mind, even a H-4 style headlight bulb has filaments.

[Guest]

If your bulb socket looks a little melted, you might want to try a ceramic socket.

[gr333nyboy]

ok, ta muchly.

[argonsagas]

A loose wire or contact seems likely, but also look at the socket itself for corrosion or poor contact surfaces.

When the bulb gets hot it expands and so does the socket/contacts, and the expansion may be affecting the contact area so that it cannot handle the current, but when it cools for a moment and shrinks then contact is restored.

[Guest]

If you have some dielectric grease lying around, that would help, too.

[gr333nyboy]

A loose wire or contact seems likely, but also look at the socket itself for corrosion or poor contact surfaces.

yes, this was it i think, it looks like one of the connectors was ill-fitting and a bit dodgy, its now gaffered together. so hopefully that will do it. i also changed the bulb to just be on the safe side.

thanks for the thoughts on this.

[850 Combat]

You might replace the fuse too. any connection can be intermittent.

[gustovh]

You might replace the fuse too. any connection can be intermittent.

This happened to me this year at the TMLC rally, the fuse looked good but was not.
V

[gr333nyboy]

You might replace the fuse too. any connection can be intermittent.

thanks, but it was only the headlight that cut out, the backlight was still fine, wouldnt everything go off it was the fuse? seems ok (so far) anyway...

[posplayr]

thanks, but it was only the headlight that cut out, the backlight was still fine, wouldnt everything go off it was the fuse? seems ok (so far) anyway...

If you have a fuse box then the headlamp is on a different circuit from the signal (brakes/blinkers) circuit.