Testing safety relay?

barelycompetent

barelycompetent

81 XS650 Special
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Hi all, its me again lol. I just recently had my 1981 charging system completely gone thru because my headlight was not coming on when the bike was started. Turns out I had a bad rotor, got that all replaced and fixed up and the bike was charging and running like it was supposed to, headlight working just fine. Well I cafe'ed it over the winter, and I relocated some of the components like the TCI box, the RLD, and the safety relay, all mounted on a metal plate I welded on to the back of the frame. I did not chop, or cut any of the wiring for these components, just relocated them. I just wired in a new fuse box as well, switched from the glass fuses to blade fuses. When I start the bike up it was instantly blowing my headlight fuse. Took me about 3 fuses before I started checking all of my connections, Im slow like that. What I found was that where I had mounted the safety relay to the metal plate, the contacts on the bottom of the relay were grounding out to that plate and blowing the fuse. Once I straightened that out, the headlight came on when the bike was running. Took it for a spin and ran out of gas right around the corner from my house. No big deal, put in fresh gas, fired it up and now my headlight is out again. I checked the fuse, its good, so I went to the safety relay. Heres what I have checked so far, dont know what else I can do from here. I checked for 6 volts on the yellow wire, and I have that going to the relay. There are two red/white wires coming from the relay, I have 12 volts on one of them, and nothing on the other. When I take a jumper from the red/white to the blue black the light comes on. I have followed curlys charging guide, just to make sure that its not my charging system again, and that all checks good. My readings at the safety relay check good as far as I know, Im getting the proper voltage needed to trip the safety relay, but my headlight is still not coming on. Is there anything else I can do to check the relay, so that I can determine once and for all if that is the bad component? Am I checking it correctly? Can I bypass it if it is bad? Sorry for the long post, and I appreciate any replies. Its so frustrating, Im so close to having this bike done, it its not one thing its another.
 
Ok, well I did some more searching and here is what I came up with. I followed this guide, very helpful, http://www.mikesxs.net/ken_maxwell/SafetyRelayOperation.htm, and when I turn the key on I get 12volts at both r/w wires, and the r/y wire. When the bike is running I get 12volts on the r/y wire, 12volts on the one r/w wire, 6 volts on the yellow wire, and nothing on the l/b which Im assuming is the light blue/black wire because thats the only blue one there lol. So I hooked it up to a 6volts charger to the yellow and black wires, and I can hear a click from the relay, but when I measure my resistance between the blue wire and r/y wire I get no reading. According to the guide its supposed to be 0 hms, but I get nothing. This indicates to me that my safety relay is bad. So should I replace it, or bypass it? If bypass how do I do that? Pics would be great lol.
 
Your SR is working for the "Starter motor cut-off" function but not the "Headlight turn on" function. If I were you, I would just wire in a switch from the red/yellow to the blue/black. Leave the switch off when starting the engine, and then select it on as you start driving.

That is exactly how my 78SE now works. My 78SE came with both the SR "Headlight turn on" function and it also has a "Lights" switch on the right handlebar. I prefer to have control of the headlight, so I disconnected the blue/black at my SR. My headlight now only works from the "Lights" switch.

Yamaha removed the "Lights" switch in 1979.
 
That sounds like a good plan to me. RG where did you intercept those wires at, and where did you put your switch at? If I put my switch on the handlebars somewhere, do I run the wires back to the safety relay, or is there a place in the headlight bucket I can intercept them? Also just so Im clear on the circuit here lol, I should run a wire from the r/y wire to one side of the switch, then from the other side of the switch to the blue/black wire? Then once the bike is started I can just turn the switch on and turn on the headlight? Just trying to make sure I have it all straight. Thanks for the advice.
 
Or can I just forget about a switch and run a jumper from the r/y to the blue black and that way the light will cut off when the I shut the bike off?
 
There is no intercepting of wires on the '78 model. You simply disconnect the blue/black wire where it plugs into the safety relay. The handlebar on-off switch came on the bike stock, it just ceased to function when the relay kicked in. Disconnecting the blue/black wire takes the relay out of the picture.
 
5twins, I have an 81, dont know if that makes a difference or not. If it doesnt then I will just disconnect the bl/b wire as suggested and go from there. Thanks for the advice.
 
barelycompetent said:
Or can I just forget about a switch and run a jumper from the r/y to the blue black and that way the light will cut off when the I shut the bike off?
Click to expand...

Yes, you can do that, but the headlight will be on when you are starting the engine. That tends to pull the voltage down, but would still work.

That's why a simple switch is better. You need either a jumper wire or a switch to get the headlight to work.
 
retiredgentleman said:
Yes, you can do that, but the headlight will be on when you are starting the engine. That tends to pull the voltage down, but would still work.

That's why a simple switch is better. You need either a jumper wire or a switch to get the headlight to work.
Click to expand...

Ok, so I have RG telling me to wire in a switch, and 5twins telling me just to remove the bl/b wire from the relay. LOL Im confused. If its as simple as removing the one wire I would rather do that, but Im not sure if my bike being an 81, if that makes a difference. Also if I do have to wire in a switch, where did you wire it in at RG? Run wires from the switch on the handle bars to the SR, and if so then a wire from the r/y to one side of the switch and from the other side of the switch to the bl/b wire? Is that correct? Like I said if its just as simple as removing the one wire, Im all for that, but if I need to wire a switch I will. I just want to get this thing done and back on the road lol. Thanks for the responses so far.
 
I'm sure the year does make a difference. The wiring harnesses changed. If you just unplug the blue/black wire from the relay, your headlight won't work at all. You need to send power down that wire to the headlight. The relay was doing that but now it stopped.

The reason simply unplugging the blue/black wire works on the '78 model is because it has two separate power feeds to the headlight, one through the handlebar switch and one through the blue/black wire. When the motor starts and sends power through the safety relay to the blue/black wire, that over rides the handlebar switch. The light comes on no matter what position the switch is in. Most of us don't care for that government mandate and have figured out how to "fix" it.
 
Ah gotcha. Looks like its off to radio shack for me. Thanks for the advice, Im gonna wire in a switch and call this one done lol. There is a used SR on ebay for 35 bucks shipped, and I thought about picking it up but I dont really want to put a used part in that could just fail down the road anyways. Looks like a switch it is.

5twins said:
I'm sure the year does make a difference. The wiring harnesses changed. If you just unplug the blue/black wire from the relay, your headlight won't work at all. You need to send power down that wire to the headlight. The relay was doing that but now it stopped.

The reason simply unplugging the blue/black wire works on the '78 model is because it has two separate power feeds to the headlight, one through the handlebar switch and one through the blue/black wire. When the motor starts and sends power through the safety relay to the blue/black wire, that over rides the handlebar switch. The light comes on no matter what position the switch is in. Most of us don't care for that government mandate and have figured out how to "fix" it.
Click to expand...
 
Many of the chopper guys remove them. Maybe you could get one cheaper here in the classifieds.
 
Just posted in the classifieds. Thanks RG and 5twins for the help. If I cant find a replacement then its time to wire in a switch. At least I figured it out with the help of this forum! Maybe a name change is in order, instead of barelycompetent, I should change it to somewhat competent lol. Im getting there, if its not one thing, its another with this bike. I guess I fried it when I was trying to figure out if it was my wiring or charging system again. It worked one time yesterday when I found it was shorting out, then after running out of gas, it wouldnt work again, sigh. At least I got it now lol.
 
Found a guy locally that gave me one for free, and plugged it in and now have lights again. Thanks for all of the replies and advice, if it happens again I will just bypass it and go!
 

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