Safety Relay gone bad?

X

xs650dude63

XS650 Addict
Messages
319
Reaction score
33
Points
28
Location
Michigan
Hey everyone, I have been trying to troubleshoot my headlight not working, I have a 1980 xs650 special, while the bike was running, I pressed the starter button and the starter worked while the bike was running, I heard the safety relay controls the starter from working and turns the headlight on. If my headlight isn't working and the starter button works while the engine is running does that mean I have a bad safety relay?

I took the safety relay off the motorcycle, the bolts that's hold it to the bike are about an inch and a quarter long, and the relay is loose on the bike, is this right, or is it supposed to be tight on the motorcycle?
 
Last edited:
Sure sounds like it. I'm pretty sure they come apart although I've never done it. I think they're just old fashioned mechanical relays with spring tensioned points arms that snap in and out of contact. Maybe they're dirty or stuck from corrosion. Worth looking at before buying a replacement.
 
The relay has rubber bushings with steel spacers that the bolts go through. With the bolts tight you can wiggle the relay around.
Another thing to check for is voltage on the yellow wire, it comes up from the stator and goes to the safety relay.
As the engine starts and the alternator starts to create voltage, some of this voltage flows on the yellow wire to the safety relay. As engine speed picks up this voltage rises, at about 4.5 volts it trips the relay.
If your alternator isn't working your safety relay won't get the voltage to trip.
The yellow wire has a single plug in connector above the transmission. Next to the big connector coming up from the stator, check to see if it is plugged together.
Your relay may be ok.
One test is to unplug it from the harness. Use jumper wires to connect the black to ground, run one from battery positive and touch it to the yellow wire, you should hear it click.
One way to test it's voltage is to connect flashlight batteries together, I use short pieces of wire and solder them from positive to negative, Each battery is about 1.5 volts. 3 hooked in series gives you about 4.5 volts. This might trip the relay, if not 4 make six volts and should trip the relay.
Yes, I know the yellow wire isn't DC, it's not really AC either. More of a pulsing DC, The relay don't really care.
If your relay passes these tests it's ok.
If not, then all these chopper/bobber guys that eliminate the e-start might sell you the one they take off.
Leo
 
I checked the relay by using jumper wires and the relay clicked, so I assume the relay is good, while I had the bike idling I was getting 12.75 volts from the battery as the bike idled it dropped down to 12.70 and stayed there, does that mean the charging system is good, if not is there another way to check the charging system?
 
Rev the bike while checking the read-out at the battery. It should rise, ideally to around 14 volts by the time you get to 3 to 3.5K RPMs. If you get no change in the voltage as you rev the bike, you're not charging. That 12.75 you're reading now could be just the charge already in the battery.
 
I did rev it, I had 12.61 @ 1500 RPMs and 13.00 @ 3000 RPMs. it wouldn't go higher then that. I did put new brushes in. I don't know how to check the ohms on the slip rings, I don't even know what setting to put on my multi tester to check the ohms.
 
Looks like you're getting a quarter volt of charging power, lol. I don't think that's enough. It takes 4.5 volts to trip the relay so that's not happening. The relay probably is fine.

You're looking to see 4 to 6 ohms across the slip rings so that would mean using a very low ohm scale on the meter. You have to remove the brushes to get a proper reading though. They tie the two rings together. You can either remove the brushes or pull the alternator off with them still in it. Personally I find it easier to pull the alternator. It makes it lots easier to get the meter probes on the slip rings and you can clean them too while you're in there. Sometimes bad charging is nothing more than dirty slip rings. The brushes can't make good contact with them. A little chrome cleaner on a rag cleans them up quick and easy. Here's my rotor with one ring cleaned, one not, using chrome cleaner .....

SlipRingCleaning.jpg
 
Dude, be aware that unlike pre-1978 versions, your safety relay is really a module with two relays mounted together. One is a normal-off relay that turns the lights on when it senses power through the yellow wire, the other is a normal-on relay that disables power to the starter solenoid when the yellow wire is powered. That's why your SR has two domes, unlike earlier versions.

Call me paranoid, but I'd only trust a rotor that metered out at 4 ohms if it had been wound at Custom Rewind of Birmingham, AL; they use heavier gauge wire than Yamaha did, so that the rotor magnetizes strongly at lower resistance. On a rotor with original windings, a 4 ohm reading means that resistance is breaking down due to faulty insulation. I once metered out an original rotor and adjusted the voltage regulator before a rally, and read a spec 5 ohms and spec output from the alternator. 30 miles into the ride, the main fuse blew and the charging system failed; the rotor had developed a dead short. Since then I've considered rotors with original windings as being fit for use only as emergency units or rebuildable cores.
 
Last edited:
I checked the OHMs and I got 5.3, I think thats a good reading, I think I need to clean the rings so I will remove the alternator and give them a good cleaning and see if that helps.
 
Well, like they say if something is going to go wrong it will. I cracked the left side cover putting it back on, I was being carefull torqueing to 6 ft pounds, it must not have been lined up right, anybody know where I can get a nice condition left side cover?

I put the alternator back on, when I tried to start it it seems to crank slower, I noticed a little bit of sparking inside the stator, is this right, should it spark a little? Thanks!
 
Last edited:
I finally got the alternator aligned right, no sparks, its hard to see if the alignment pin is aligned with the slot, it still seems that the bike is cranking over slower then it was, I am going to charge the battery overnite and try it tomorrow, I hope I didnt warp the rotor, if that is possible. Is there a torque setting for the alternator mounting screws? Can you over tighten them?:banghead:
 
All good on the alternator, I cleaned up the slip rings real good, got 5.3 OHMs across the slip rings, the bike started right up, idled pretty good, checked the battery voltage, 12.60 at idle revved it up to 3500 RPMs got 13.23 volts.

Looks like I have a charging problem, if it wasn't for the headlight not working it wouldn't be that big of a problem, I don't really need turn signals, but I do need a headlight, especially at night!!! What should I do??? a Thanks!!

I did call custom rewind and they will rebuild my unit for $135.00, is this the way I should go, is there a cheaper way?
 
Last edited:
That's not a bad price... and a rewind is my recommendation. Pretty sure a new repop unit will be close to that, and the quality may be iffy. But if yours is testing good...why bother with the rewind. You may just need a new reg/rectifier for your charging issue?
 
Do I set my multitester on 200 ohms setting or 200k?

With my multitester skills, i might be better off buying a new one, they have them for $35.00 on ebay with free shipping.
 
Last edited:
Look for a good meter with a low resistance scale; Rx1 (1 ohm) is best for accurate readings in the single-digit range.
 
xs650dude63 said:
Actually, I was talking about a new regulator.
Click to expand...

Now your talking but first,
Have you wandered through the charging guide?

http://www.xs650.com/forum/showthread.php?t=10561

Did you check all your wiring connections? Yeah that's a big project but a couple of meter measurements can help. #1 check your ground strap, the cable form battery to frame. remove clean ends wiggle both connectors look for green or gray corrosion. Charge your battery (again) then start measuring your plus 12 start at the battery teminal.

On an 80 special with the one piece regulator rectifier you could have one of two issues a bad rectifier or a bad regulator. First is the short the "green wire brush" that will make the alternator go full charge all the time.

http://www.xs650.com/forum/attachment.php?attachmentid=18923&d=1341592645

Then you can test the rectifier and I'm kind of guessing that's your problem since you have "some" charging, an electronic regulator is usually all or nothing.
 
+1 to all of the above!

If you have to change the reg/rec and want to do it on the cheap, use the automotive components recommended by pamcopete and others; search and you'll find it. Otherwise avoid cheap reg/rec units and anything, cheap or not, from Electrosport, and get one from Rick's Motorsports Electronics.
 

Similar threads

delagem
Starter Safety Relay help?
Replies
5
Views
828
Team Junk
Team Junk
lil2lo
Safety relay question
2 3
Replies
53
Views
4K
dps650rider
D
Mannyroad
XS650SF - removal of light checker, RLU & Safety Relay
2
Replies
28
Views
2K
Jim
Jim
L
Newbee Electrical Questions…
2 3
Replies
48
Views
4K
Bountiful
Bountiful
ANXS650
Press Start Button, then Nothing
Replies
3
Views
424
robtattoo
robtattoo
Back
Top