Headlight, tail light working. Not working. Working....??

[greybeard52]

So last fall I went for a ride with my son and when we returned home, the headlight and tail light on my1986 R80RT weren't working. I turned the switch on and off. I can hit the flash function and the bright comes on. I decided to order a new relay from Wunderlich before I took off the gas tank to look for a short. Meanwhile winter set in, here in Wyoming, so today is the first day I have warm (53 degrees) weather to roll the bike out of the garage and drain the tank and take it off. I turned on the ignition and the headlight and tail light were still not working. I cranked the engine and the headlight and tail light came on. I turned off the engine and cranked it up again and they are on. I did this a few times and they came on each time. And the lights come on when I just turn on the ignition and don't crank the engine. And I can switch to high beam and low beam. So apparently the headlight cut out is working to use the power from the battery for cranking the engine.
It could still be a short somewhere, but before I drain and remove the tank, am I missing something? I did take the switch on the handlebar off and looked for any abnormal things lurking in the mechanism. It's pretty much sealed so I couldn't really clean anything. I did notice that the switch is not made in Germany, but in some Asian country. I forget which one. So it has been changed out at least once.
Two heads are better than one when solving problems. Any thoughts would be appreciated.

 

[20774]

About the only connection I can see between the headlight and tail light, besides ground, is that they seem to have a connection on the light relay. There is another power compliment through the ignition switch...obviously.

 

[greybeard52]

About the only connection I can see between the headlight and tail light, besides ground, is that they seem to have a connection on the light relay. There is another power compliment through the ignition switch...obviously.

Are the headlight relays an all or none deal. They either work or don't work? If that is the case, it seems like my headlight and tail light wouldn't be back on which means a short or the switch on the handlebar is funky.

 

[pglaves]

I think it is time to disconnect, clean, and reconnect all of the wiring that connections for the headlight and tail light circuit.

 

[greybeard52]

I think it is time to disconnect, clean, and reconnect all of the wiring that connections for the headlight and tail light circuit.

I agree. I'm draining the tank after lunch. Thanks guys. Or should I say Y'all? I moved to Wyoming from Texas 31 years ago and have picked up saying You guys.

 

[20774]

I'm draining the tank after lunch.

Why are you draining the tank? If I have fuel in my tank, I can find a place to park the tank, with some padding, while I work. Seems like an extra step.

 

[greybeard52]

I drained the gas tank with my super gas pump. I removed the tank and checked for shorts from frayed wires. I removed the relay and cleaned the connection and installed the new relay. The negative ground cable from the battery to the engine was pretty greasy and dirty. I cleaned it thoroughly and reconnected it. I remember when i worked at a gas station in 1973 while I was in college, the mechanic that worked there, back when gas stations were full service, told me that if a customer comes in complaining about electrical problems, the first thing to check are the battery terminals. He said most times if you clean those, the problem is solved. I’ve had that problem with a few of my cars over the years. I’m not positive, but i wouldn’t be surprised if cleaning that dirty ground cable connection solved the problem. The bike seems to work fine now. I removed the factory liner from the gas tank two years ago because it was flaking off and causing my carbs to pee on my boot. Since i was removing the tank today, i decided to pump the gas out of the tank to look for flakes. I also removed the float bowls to check for debris. The gas looked clean as did the float bowls. I haven't had problems with leaking carbs so i guess all of the liner is out. It’s getting cold and snowy tomorrow. No riding for a while. Now why did i move to Wyoming from Texas? Oh yeah, I like to snow ski more than once per year.
Ride safe!