low voltage to relay

[Stray Bullet]

can anyone tell me what the low voltage is supposed to be to the
headlight relay? i have a replacement lined up, thanks to dave
hogue!!!

[skids]

Re: low voltage to relay

Dan, the 78 models used one of the phases coming from the alternator (I think). This phase is more like a sine wave (AC). This is probably the reason that the relay needed to be a "latching relay." If the volt regulator is properly working, that voltage should be something like 14.5 volts (rms?), the same as the charging voltage, and same as the voltage to nearly everywhere else.

Originally posted by Stray Bullet
can anyone tell me what the low voltage is supposed to be to the
headlight relay? i have a replacement lined up, thanks to dave
hogue!!!

[skids]

After fishing through the other threads, I noticed that you have a "79SF with 81H front end, lights, and instrumentation." I know the later models were supposed to have a diode in line with the relay unit, although I don't know why. I still say, yank out the relay and put a REAL automotive one in there and use a switch on the handlebars to power the realy instead of that "always on when engine is on" system!

[Stray Bullet]

sid,

i cant recall why, but i seem to remember that the ALT voltage to the relay was reduced. isn't this the function of the diode? (electrical wizards, chime in!!) i only have access to my haines manual, and it doesnt show a diode on the SF, but its included in the G/SG diagrams. i'm not sure if the SF has a diode or not!

i DO know that i was getting approx. 2.9v from the yellow (ALT) wire in the relay connector, which led me to post my question here:

is this the correct voltage?? even close? if it isnt, then i'm dealing with the wrong 'problem'. perhaps it is the volt regulator??

the bike starts right up, after replacing the batt. after riding home 40 miles with my high beam hot-wired, my batt from last year was fried. had several cells at only 1/4 charge, and it would not rejuvenate. it was a year old, cheapo from advance auto. i replaced with walmart special.

all that said, i agree 100% with you on the switched light. that was a winter project that i never got to. i have a '78 right hand control. it just needs cleaned up, etc, and wired up.

having proven my skill & knowledge level here concerning troubleshooting XS11 wiring (honestly, i've wired up tagalong trailers, truck lights, and even houses), you can see that this isnt a 2 hour project for me, at least at this point. i am open to any pointers, write-ups, etc... from you, or anyone else... except for maybe Irish... (ha!)

thanks for yer time, skids.

[dntemp_ca]

I have a 78E with the headlight switch on the right handlebar.
Does anyone know how to mod the wiring to enable the switch to turn the headlight OFF when the engine is running? This should allow decent charging during daytime running and enable adequate lights on power for infrequent night time riding.

[rainbowshooter]

Is anyone interested in a new wiring harness and wiring diagram? I am currently upgrading a 78E with new style fuse holders, relays, and a couple of options right now I have only the ignition just about done but as I looked at the lights I think there are a lot of things that can be different and less confusing, actually I already found a lot on the ignition side.
I tried to use all the original connectors wherever possible.

[dntemp_ca]

I'd be interested in that, Rainbowshooter. I want to work on my parts bike and get it running (some day). It's a 78E also. Since my main bike is in stock full dress touring setup, my plan for the partzer is to make her a mild custom...just the basics and maybe some colors similar to the Merriam Cycles treatment. A simplified wiring scheme would be great.

[rainbowshooter]

Ok I should have the rest of it done soon. I will clean up the diagram and send you a copy along with a couple photos and parts list.

[dntemp_ca]

Your good work would be an excellent article to post in the Tech Tips on this website.
Thanks!