Electrics

yellowdog

yellowdog
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Morning all,I thought it was too good to be true with my rebuild xs2.
Got it all back together engine great, stopped the fuel taps leaking, brakes ok. But no lights ,nothing . annoyingly they worked previously so it must be something I've done .
I've got no brake light or rear lamp no headlights all I've got is a neutral light and the horn.Surely brake lights should work independently of lights ? Could it be the switch isn't grounding?
I took the light switch apart to check it and then the fuse blew since then nothing works could I have blown something else ,rectifer regulator or some other component? I'm useless with electrics haven't got a clue .I suspect the switch but I don't know .These early switches are grounded at the switch by a small tap that touches the handlebars so maybe not the ground ,Sorry to go on but need some advice please
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Stock wiring is not my forte, having said that the Horn circuit has power to the horn and the circuit is completed at the switch block connecting to ground when the horn button is pushed.
If your horn is working the switch block ground is ok.
The light switch is on the power side of the circuit, power goes through the switch then through the lamp filament to ground. The earth at the switch is not related.
It is unlikely you have blown the regulator rectifier but until you find the fault it might pay to unplug it.
The XS2 has one fuse from the diagram I am looking at so you will have to methodically work your way through the harness to find the fault.
Look for damaged wires and recheck the work you did is correct (something plugged into where it shouldn't be sort of thing).
 
That connector on the picture needs service and cleaning .Might not be the cause to your problems .But might as well do it.
As the connectors and switches. It is seldom the wire itself giving problems according to my experience
If it is a stock wiring aka old mechanical regulator and Stock rectifier
I give it a better chance than 90 % they still are OK
But the regulator can still after the fault finding be replaced
But not before it is sorted out.
That is the advantage with the old it can take more beating

Feel free come with more description someone will help out
 
Update on the lights .
I discovered this morning that the problem is the switch internals .The very small springs that push the connectors together are either not strong enough or not long enough, possibly caused by myself fiddling with something 52 years old that didnt want to be fiddled with ,! I made a small shim to enable the spring to be closer to the connection and behold we have light ,it's a bit of a bodge but it's working.
Still no brake lights though,is there a way to check the brake switches are ok before I buy new ones ie connect the wires together and bypass the switch neither front or back work ,they weren't working when I got the bike so possibly an existing problem.
Thanks again .
 
Update on the lights .
I discovered this morning that the problem is the switch internals .The very small springs that push the connectors together are either not strong enough or not long enough, possibly caused by myself fiddling with something 52 years old that didnt want to be fiddled with ,! I made a small shim to enable the spring to be closer to the connection and behold we have light ,it's a bit of a bodge but it's working.
Still no brake lights though,is there a way to check the brake switches are ok before I buy new ones ie connect the wires together and bypass the switch neither front or back work ,they weren't working when I got the bike so possibly an existing problem.
Thanks again .
Can you measure the springs? The ones in my kill switch measured 3mm x 10mm (as near as I can tell). I am expecting a pack of ten anytime soon to fix my kill switch. If they fit your light switch I can pop a couple in the post.

To test the brake light switch, use a multimeter. Closed the resistance will be low (brake actuated). Open it will be open circuit (brake not actuated). I tested my rear brake light switch a couple of weeks ago. I gave it a spray of WD40 down the little plunger, works just fine now.
 
Can you measure the springs? The ones in my kill switch measured 3mm x 10mm (as near as I can tell). I am expecting a pack of ten anytime soon to fix my kill switch. If they fit your light switch I can pop a couple in the post.

To test the brake light switch, use a multimeter. Closed the resistance will be low (brake actuated). Open it will be open circuit (brake not actuated). I tested my rear brake light switch a couple of weeks ago. I gave it a spray of WD40 down the little plunger, works just fine now.
The hole they go in is 4mm and one spring is about 5mm the other is about 7 mm looks like it's been dodged before .I'm going to try a ball point pen spring 🤔
 
The hole they go in is 4mm and one spring is about 5mm the other is about 7 mm looks like it's been dodged before .I'm going to try a ball point pen spring 🤔
No problem. If the ball pen spring doesn't work, I should have my springs before the end of the week. (I hope). 3mm x 10mm long springs can, of course, be cut to length if you want to try it.
 
You are making progress.
The brake light circuit is 2 normally open switches in parallel, if either switch closes the lamp should operate.
Both switches have a brown feed wire.
Starting at the most obvious check the lamp, and lampholder .
Check you have power on one side of each switch.
If you have power on one side bridge a switch, if the lamp does not light check for wiring continuity.
I have found the rear brake mechanism on XS 650's a pain to adjust when starting from scratch so good luck.
 
You are making progress.
The brake light circuit is 2 normally open switches in parallel, if either switch closes the lamp should operate.
Both switches have a brown feed wire.
Starting at the most obvious check the lamp, and lampholder .
Check you have power on one side of each switch.
If you have power on one side bridge a switch, if the lamp does not light check for wiring continuity.
I have found the rear brake mechanism on XS 650's a pain to adjust when starting from scratch so good luck.
Thanks ,bulbs are new and tail light is working,just seems coincidence that neither front or back is working
 
No problem. If the ball pen spring doesn't work, I should have my springs before the end of the week. (I hope). 3mm x 10mm long springs can, of course, be cut to length if you want to try it.
Thanks ,I've ordered a multimeter today not that I know how to use it but I'll figure it out .
 
I am not sure about the XS but I have put a dual filament lamp in the wrong way before.
You are not supposed to be able to do that with the lamp having offset bayonet pins but I managed to. Have a look it may be that easy.
 
Yes both switches are connected such that they can be un-plugged and the harness side of the connections plugged together to create "always on", handy for troubleshooting.
I'd start at the connections above the rear fender. Supply +12 to the yellow, does the bulb light? if so start working back from there.
From the tech menu,
72-xs2-circuit-diagram.jpg

Print out the wiring diagram, always a first step in trouble shooting electrics.
No multi meter needed for this type work, a jumper wire is your friend, I also keep a "turnsignal bulb" with a couple of two foot wires with alligator clips at the bench to look for where +12 is and isn't and all you'll need for work like this.
The brake switches are notorious for being mis-adjusted and having poor internal connections.
 
Thanks as always
I got a multimeter anyway (there cheap enough)I'm not sure if I'm doing it right but bear with me please .I set it continuity and unplugged the rear brake switch ,I touched the points to the exposed wires and meter showed what I assume is a low reading so that's good ? Next I put the points on the wires coming out of the switch and meter didn't move just showed 1,I did the same with the front brake switch and got the same result so does this mean the switches are faulty .see pics thanks
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Thanks as always
I got a multimeter anyway (there cheap enough)I'm not sure if I'm doing it right but bear with me please .I set it continuity and unplugged the rear brake switch ,I touched the points to the exposed wires and meter showed what I assume is a low reading so that's good ? Next I put the points on the wires coming out of the switch and meter didn't move just showed 1,I did the same with the front brake switch and got the same result so does this mean the switches are faulty .see pics thanks View attachment 327311View attachment 327312View attachment 327311View attachment 327314
You are doing it right. The 1 means open circuit, switch is open. Actuate the switch, switch is closed and it should show a low resistance. Put simply, if you get different readings across the switch when you pull it, it's fine. Hope that helps.

I have to say, anyone with an old bike really needs a multimeter. Essential tool for trouble shooting, setting points timing etc....

Recommend you buy a set of leads with crocodile clip ends for the meter. Then you can do jobs that need three hands!
 
Set multi meter to 200 ohms setting to check switches.
Set multi to 20 DC volts, ground balck lead, check that you have +12 on the brown harness wire, ignition on.
Trust me, this stuff is easier with a light bulb tester,.
Yes, there's something to be said for keeping stuff simple. A multimeter should be in every old bike owners toolbox though. They're so cheap and readily available, everyone should have one. Probably as useful as a torque wrench. The other indispensable tool that everyone should own.
 
You are doing it right. The 1 means open circuit, switch is open. Actuate the switch, switch is closed and it should show a low resistance. Put simply, if you get different readings across the switch when you pull it, it's fine. Hope that helps.

I have to say, anyone with an old bike really needs a multimeter. Essential tool for trouble shooting, setting points timing etc....

Recommend you buy a set of leads with crocodile clip ends for the meter. Then you can do jobs that need three hands!
So when I put the leads on the switch and pull down on it ie activating it the reading still says 1 so switch broken ?
 
Set multi meter to 200 ohms setting to check switches.
Set multi to 20 DC volts, ground balck lead, check that you have +12 on the brown harness wire, ignition on.
Trust me, this stuff is easier with a light bulb tester,.
So using bulb method it's effectively by passing the switch?
Will the brake light work if one switch is broken or do they both need to be working ?
 
So when I put the leads on the switch and pull down on it ie activating it the reading still says 1 so switch broken ?
In principle yes. Pulled or not pulled, there needs to be a difference on the multimeter. When you pull, you're closing the switch. No change when pulled/not pulled means a problem switch.
I got mine working OK by spraying WD40 down the little rod that pulls. Squirt of WD40 and pushing/pulling the little switch rod got mine working fine again. Worth trying on yours before you get a new switch.

Edited to add - I've removed the front brake light switch on my 1977 bike. Of course it's MoT exempt, but UK regulations didn't mandate a front brake light switch as well as a rear one back in 1977. So, provided there's no switch on the front brake, it's fine with just a rear brake light switch. In my opinion.
 
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