Intermittent tail light

[bbelk]

On my last road trip, my tail light crapped out. I pulled the bulb and cleaned the contacts, but it didn’t seem to help. Then the next time I check its working and for the rest of the trip it went back and forth between working and not working. On the last night, it defiantly was not working as the sun set at 80 MPH on Interstate 10, where its legal, unless of course your tail light doesn’t work.

Is there something on this 1975 R90/6 that might cause those symptoms? If not, how do I track it down.

Thanks
Brad

[the quinner]

On my last road trip, my tail light crapped out. I pulled the bulb and cleaned the contacts, but it didn’t seem to help. Then the next time I check its working and for the rest of the trip it went back and forth between working and not working. On the last night, it defiantly was not working as the sun set at 80 MPH on Interstate 10, where its legal, unless of course your tail light doesn’t work.

Is there something on this 1975 R90/6 that might cause those symptoms? If not, how do I track it down.

Thanks
Brad

Clean the chassis ground at the left coil...remove the bolt, clean the ring terminals and the frame side...re-install bolt and smear some protective grease over the whole shebang. If your bike has a connector to the left of the battery where the subframe wiring connects to the main wiring harness, disconnect it and clean those connections, too. Might as well disconnect and clean the connectors behind the tail light reflector while you're at it.

Are you using a stock bulb? ...or, an LED bulb? Some of the LED bulbs have enough mass that over time, they wiggle the bulb socket to the point where it doesn't make good contact...that is, they act as a lever...prying the socket wider than it should be.

[Major Softie]

And, that stock bulb CAN develop an intermittent failure. They aren't common, but it can happen, so it could simply be the bulb.

Quinn's suggestions are more likely the issue, but....

[dwerbil]

And, that stock bulb CAN develop an intermittent failure. They aren't common, but it can happen, so it could simply be the bulb.

Yep, I've come across that little scenario before. Just throw in your extra bulb and try it out for a while.

[Deleted User 72]

I have sometimes found the little solder nipples on bulbs worn or dimpled when the bulb won't light. Probably from vibration, as I've never seen it on a car. New bulb.