Headlight Relay Question

[mstic2000]

The last few days my battery is draining down for some reason. I had the battery tested under load at Batteries Plus and it is good. I noticed that when I went to disconnect the ground from the battery and then touch it again the headlight relay clicks once, disconnect the ground and it clicks once. I've never noticed this before. Another thing just started happening is when I turn the ignition on the headlight comes on before I start the engine. It always came on when I started the engine. I keep the battery connected to a trickle charger over night and I get a full charge of 13. something and the battery will hold a charge of 12.7v disconnected from the bike. Checked the charging at 1100rpm and I get 11.98v. Ride for a few hours and it's down to 10v and starter won't spin. I tried a spare headlight relay that is good and same thing is happening. I cleaned the terminals to the headlight and no change. Does this sound like a short in the wiring somewhere?

I've had problems with the headlight going out on me when I was riding and when I took the headlight out and wiggled the wires around it would come on again. I haven't had that problem since last year.

[ManagerMike]

Don't shoot the messenger, but your charging system is not functioning based on the info you have provided. Once your electrical system falls below a certain voltage (usually 9-10 volts) all kinds of gremlins begin to show up.
The headlamp relay is energized by the generator to begin with, therefore I would be inclined to believe your symptoms are being caused by a fault in the generator/ voltage regulator circuits.

[mstic2000]

I'm inclined to agree with you because it is only charging at just under 12v at 1100 rpm. When I rev the motor to 3000 rpm it dips down to 9-10v for a second and then comes back up to just under 12v. I know there's a good post on here that I saved about dead battery. I'm going to have to go through and read the whole thing of where to begin. I was hoping it was just a short somewhere in the headlight wiring but ya, I think you are right.

[natemoen]

I'm inclined to agree with you because it is only charging at just under 12v at 1100 rpm. When I rev the motor to 3000 rpm it dips down to 9-10v for a second and then comes back up to just under 12v. I know there's a good post on here that I saved about dead battery. I'm going to have to go through and read the whole thing of where to begin. I was hoping it was just a short somewhere in the headlight wiring but ya, I think you are right.

You should be at full charge at I believe 2400 RPMs and that should be more in the 14V range. If your at less than 12 volts across the battery at 3000RPMs your charging system is not working. You need to start looking at that.

[mstic2000]

Ya, I found this thread and am going through it right now. Lot of good info on what to do about a faulty charging system. Thanks.

Will a low battry keep an XS11 from starting?

[ManagerMike]

Just a topic related FYI... the proper charging voltage for any 12 volt DC electrical system is 13.5 to 15 volts, ideal charging voltage is 14.2, but that is seldom seen. 14 volts or close is norm. If you see anything less than 13.5 volts at the battery, it is not being charged. Anything more than 15 volts will not only overheat and boil the battery, but will also have deleterious effects on your lighting systems and anything electronic, i.e. the TCI module. This also applies to your automobiles.

[3Phase]

Mstic, do you have a headlight switch on the right handlebar control that perhaps got left on? That will make the headlight come on when you turn on the ignition.

If not, you may have a bad regulator/rectifier or a shorted connector. Unplug both connectors and see if the headlight still comes on with the key.

[natemoen]

Mstic, do you have a headlight switch on the right handlebar control that perhaps got left on? That will make the headlight come on when you turn on the ignition.

If not, you may have a bad regulator/rectifier or a shorted connector. Unplug both connectors and see if the headlight still comes on with the key.

Yeah the 78 should have the headlight switch. On mine the headlight will come on with the key if the switch is set to on but if its off it only comes on once the engine is started. I have my switch always on but have not had any other problems with that.

[mstic2000]

I switched out the voltage regulator with a spare one from a parts bike (Thank you Yamaha Gods!) , and all the little gremlins disappeared! I should have suspected the voltage regulator right off the bat with it charging at right under 12v instead of chasing those darn little gremlins around! Thanks all.

On The Road Again

[oldyam80sg]

Get one of the ones from Geezer and your problems will also disappear.One of the best investments i have made!

[3Phase]

Glad you got it working!