Electrical Problem

[Fddlefoot]

Please Help
I recently lost headlight and illumination in both speedometer and tachometer have checked fuses and headlamp and have all other power. Any ideas before I start tearing apart the electrical system

[oseaghdha]

check your relay under the tank stuffed up between the top frame tubes.

[Fddlefoot]

Be glad to how do I check just see if power is coming out backend??

[oseaghdha]

First check the yellow for juice when it runs.
The red should be hot.
Black is ground.
Blue is out.
Jump the blue and red you should get lights when the key is on.

[oseaghdha]

Same problem with relay

Had mine start giving me trouble.
Worked sometimes, sometimes not. I could rev it and it would latch up, or after riding for a bit noticed it was on. Did not ride at night lately.
Anyway, I checked the wires, all were doing what they should. When it was running, I could tap the relay and it would catch.
Took it apart and saw the white wire inside was supposed to be soldered to a copper strip. They did a poor job and it vibrated off, but was still laying in place. Hence the intermittant operation. The rest of the works inside looked to be in excellent condition.

Resoldered the joint and it appears to be cured.
I saw an NOS relay on Ebay: $65.00!
So, before you toss it, jimmy it open and have a look.

[tinman905]

What year and model do you have there? The lights are out on your speedo and Tach but is your tach still working sshowing the RPM's or is it jumping? If the Tach is jumping around too then it could be a charging problem .

[andreashweiss]

I have several headlight relay in my parts pile for the xs1100, used but decent, certainly you can pay ebay price if you want, but I would consider $15.00 to be the correct price for mine and that includes shipping in continental USA. Ebay is not always the cheapest source for parts. andreas

[Fddlefoot]

Round Two

Ok It is a 79 special and I just switched out the headlight relay from my 80 special and no luck as to charge put brand new battery in while doing this was for other bike but while working other night left key on so just put new one in 79 any more ideas i really appreciate the help

[egsols]

First thing as they are on seperate circuits check for good ground. Secondly, on my Special headlight will not come on until bike is running, I think it is only on the Canadian models only. If you have a headlight switch for on/off check its wiring. I also remember some bikes had a dimmer, think was only European models, not sure, but if you have one check that too.

[egsols]

Found these, hope they help.

[oseaghdha]

Try to keep up

Originally posted by egsols
..........Secondly, on my Special headlight will not come on until bike is running, I think it is only on the Canadian models only. ..................................

No, thats normal.

As above:
The Yellow wire on the relay should have 7 volts when the bike is running.
If it doesn't, you may have a problem with the charging circuit, regardless of the battery condition.

If you put a jumper between the BLUE and the RED wire on the relay plug, the lights should light when the key is on.

You have to do the tests, or you cannot trouble shoot it.
Otherwise you can just change random parts and hope to get lucky.

[Fddlefoot]

OK feel stupid

Ok jumped blue and red and tach and speedo lights came on but not headlight but if that only comes on when running would be reason why? but this is where feel stupid how do I get the bike to run since need tank off to get to relay . Thank you for all the help i appreciate it

[John]

The bike will for at least 30 seconds on just the fuel in the bowls and lines. (I can ride 1/2 mile on that small amount) All it has to do is basically just fire off and that will energize the relay and the light will come on.

[oseaghdha]

No worries. I tore half my lighting apart once because I had a burned out headlight

If you jump the red/blue it should light with only the key on. It does not need to be running.

The yellow wire is the one that has to be running to check.

It will run for a minute or two with only whats in the carbs.

You can turn the tank around backwards and hook the fuel up. If you have the Octopus, use the prime and plug the rest. Its messy and you will want a fan blowing on the motor for any extended period of time.


The red and blue seem to be functioning, so the next possible problem is the Reserve lighting Unit which also gets its juice from the blue wire. Read the link for info.

Before you go running off with wire cutters and black tape, try unplugging and reconnecting the various connectors under the seat. Sometimes they get dirty and/or loose.

[Fddlefoot]

Ok already burned fuel in carbs before this and the headlight DID NOT come on when jumped red and blue and when this started went out and replaced the headlamp so that should be good to go. Will check connections again although all seemed tight and read up on reseve lighting unit thanks