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Discussion in 'The Garage' started by Raymondo, Jun 13, 2019.

  1. 5twins

    5twins XS650 Guru Top Contributor

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    Yes, that small rubber box you found behind the battery with the 7 wires sounds like the light checker. Two versions were used on these. The Standard model used a simpler 3 wire unit. It monitored just the brake light and is easy to eliminate - you just unplug and remove it. Your Special model got the more complicated 7 wire unit. It monitors both the tail light and the brake light. Power for the tail light passes through it so you can't just remove it without adding a jumper wire to restore the power path to the tail light. Both units trigger a warning light in your dash if the brake light on the Standard or the brake or tail light on the Special burn out. Mine's gone, along with my reserve lighting unit.

    I actually had no problem with the light checker but when I switched to an L.E.D. tail light bulb, the warning light in the dash came on full time. I guess the low voltage use of the L.E.D. fooled the unit into thinking the bulb was burned out, so I removed it.
     
  2. Raymondo

    Raymondo XS650 owner, fettler, setting out on a journey

    Jim, thanks for the pointer - I have printed off the first one which will provide a useful reference & check.

    5T, thanks for identifying the lights checker. I know it works - the first time I ran the engine, just for a few minutes back in June, the bike was part dismantled and was using a fuel bottle hanging from a rafter in the garage. This bright red light in the middle of the warning cluster immediately came on and got my full attention because that's where you might reasonably expect an oil pressure warning. Glasses on and close scrutiny showed it was just a lights warning - was I relieved?

    In fact, at that point it was quite funny 'coz the rear mudguard and tail light were sitting on the bench . . .
     
  3. MaxPete

    MaxPete Life with Lucille...I suggest, she decides. Top Contributor XS650.com Supporter

    It is interesting how Yamaha put all this fancy technology into systems to alert us to the failure of a bulb....I don’t think any other bike or car maker did that.

    Sort of technological dead end / solution looking for a problem I guess.
     
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  4. Raymondo

    Raymondo XS650 owner, fettler, setting out on a journey

    Gives a bit of scope for pruning the number of wires running around though . . .

    Today, I have mostly been in the garage playing with coloured pens:

    PICT1968.JPG

    Before you can hop, Grasshopper, you must find out what's there.

    I suppose it's fun in a way?
     
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  5. 5twins

    5twins XS650 Guru Top Contributor

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    You'll need to keep up the research. That drawing you made shows some discrepancies. There is no dark blue wire going into the left control. There's a dark green for the right signal, and a normal green for the low beam. Maybe you confused one of those for a dark blue? I think the yellow/black soldered to yellows is normal but that yellow running to the headlight plug shouldn't connect to black, that's the ground. it should go to yellow (high beam). The end that goes nowhere originally went to the reserve lighting unit. The blue/yellow also originally came from the reserve lighting unit. It was the power feed to the hi/lo switch so will now need to be tied into the headlight on/off switch somehow. Normally, when you removed the RLU, you jumpered it to the blue/black to accomplish this.
     
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  6. Raymondo

    Raymondo XS650 owner, fettler, setting out on a journey

    5T - you couldn't pop round and give me a hand, could you?

    I'm certain there will be discrepancies - at the moment, I'm just faithfully recording what is there.

    For the left handlebar, I have found 11 wires - 6 go to a block connector and 5 are loose wires. The block of six has Pink (horn), Brown/White (flasher relay), Yellow/Red (flasher cancel), Yellow/Black (joins up with yellow to headlamp, tacho and nowhere), Dark Blue (goes nowhere - I think it's blue), Blue/Yellow (what I thought was indicator harness, but might have been reserve lighting unit). The single loose wires are Yellow (headlamp), Green (headlamp), Black (headlamp), Brown (l/h indicator), Green/Black (r/h indicator).

    Some of the colours are a bit hard to call. There's Brown, Dark Brown and Chocolate, as well as Black/Brown and to add to the confusion, some PO has added lots of a different shade of brown. Plus some of the older wires are faded and dirty, so its hard to discern Red/White from Red/Yellow. The Sky Blue looks like duck-egg green in some places and has faded to almost cream in others.

    There's quite a few which don't go anywhere. Often terminated with a wrap of insulating tape.

    Some of the 41 year old cabling is very brittle and faded.

    Many other wires are newer, but often these have messy soldered joints with 5 or 6 black or brown cables wound together and soldered over. I suppose these are intended to be earth (ground) wires?

    I'm hoping that as this task continues it will become clearer. Already feels as though there will be scope to reduce the complexity.

    Onwards and (slowly) upwards.
     
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  7. 5twins

    5twins XS650 Guru Top Contributor

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    The black ground wire coming out of the left switch assembly is the ground for the whole thing. Don't connect it to the headlight ground, connect it to one of the ground wires that come out of the two harness looms. The headlight ground wire also gets connected to one of those. If you connected the switch ground to the headlight ground, you will have connected together two wires that are seeking a ground. Neither has it on their own and they're not going to find it connected to each other.
     
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  8. Raymondo

    Raymondo XS650 owner, fettler, setting out on a journey

    5T, thank you for this!

    I followed the link you gave earlier for reserve lighting unit, so now I know what that is. Your dip element fails so the bike automatically switches to main bean AND illuminates a warning light to explain why the oncoming 40-ton lorry just lit up his eighteen headlamps and spots to full beam. Hahaha - absolute genius!

    The earth wires are very poor and definitely need re-doing. Things have moved on a bit since yesterday:


    PICT1969.JPG

    PICT1970.JPG


    Been doing some dissecting. That sound better than pulling it all apart wire by wire to see where it all goes.

    As noted above, the wiring is old, hacked about and of variable quality. Perhaps looks like I'm committed to fully replacing it now?

    Just hope I don't regret this . . .
     
    Last edited: Sep 12, 2019
    MaxPete and Jim like this.
  9. Raymondo

    Raymondo XS650 owner, fettler, setting out on a journey

    Well, the dissection of the old harness is now complete, new cables and connectors are on order and I'm thinking about the new wiring system. It will be a lot simpler - no light checker, reserve lighting unit or flasher cancel unit saves a lot right away. Might be a good idea to leave the safety relay, just for it's function of shutting the starter motor off as soon as the engine fires? Though I haven't worked out how that works.

    One area which seems very confusing was the - heavily modified by POs - wiring to and from the 4-fuse box. My question for the wise on this forum, those who actually understand motorcycle electrics, can I get away with just having one fuse? I would put it in the main red wire from battery to ignition switch. Or do I need to have fuses to protect other circuits?
     
    Jim likes this.
  10. Ozboy

    Ozboy XS650 Addict

    Yes it is best to have multiple fused circuits. You wouldn't want your brake light or indicators blowing your whole system and left stranded. Atlest if they blow you can make it home using hand signals.
     
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  11. Jim

    Jim I have a plan. It's something to deviate from. Top Contributor XS650.com Supporter

    Agreed. At bare minimum.... put the ignition system on a separate fuse. That way a short elsewhere on the bike wont kill it.
     
  12. MaxPete

    MaxPete Life with Lucille...I suggest, she decides. Top Contributor XS650.com Supporter

    The earlier bikes all run on one fuse (in fact, it may be that all Standards up to when they stopped building them in 1979 have just one fuse) - and the Specials all have four <I think>. I don't know the reasons for that - but it seems to be the case.

    Certainly - NOT having any fuses is a very bad idea - but one or four - either seems to work just fine. The rating for the single fuse bikes is 20 Amps.

    One the matter of the Starter Safety Relay (SSR): I strongly urge that it be retained on all bikes. I believe that the SSR functions by sensing an output voltage from the alternator - and that holds the contacts open which prevents the starter motor from being energized.

    In my view, it just doesn't make sense to risk the starter motor and all those nice little gears for the sake of a small relay. If you eliminate it, and then bump the starter button while the bike is running, you will fill the crankcase and transmission with little bits of metal debris.

    Now, I did have a problem with the SSR on Lucille. After several weeks of reliable starter operation, it suddenly stopped working altogether: the button did nothing. I tracked the problem down to some corrosion and crappola in the Starter Safety Relay - which was not allowing current to get to the starter motor.

    The SSR lives under the RH sidecover - it looks like the voltage regulator - and if you just remove the tiny little screws that secure the metal cover, you can clean it very easily (including the little set of contacter points). I did that and it has worked faultlessly ever since.

    That's my $0.02 on wiring.

    Pete
     
    Last edited: Sep 17, 2019
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  13. 5twins

    5twins XS650 Guru Top Contributor

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    Yes, all the Standard models had just one fuse, a main 20A one. That set-up on my '78 Standard has never given me any problems and I don't see the need to go through all the work involved to wire in more fuses. On the other hand, if it was a Special and already had the wiring there, I don't think I'd remove it and the extra fuses. While not 100% necessary, they are nice to have.
     
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  14. Jim

    Jim I have a plan. It's something to deviate from. Top Contributor XS650.com Supporter

    Years ago I had a bike with the single fuse. It blew... replaced it and blew again.... leaving me to hitch home to get my truck and retrieve my bike. As I recall, it was a chaffed wire to the headlight. Had the ignition system been on a separate circuit, I coulda' just drove it home and figured it out. Lesson learned, I added a fuse dedicated to ignition.... just food for thought.
     
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  15. Raymondo

    Raymondo XS650 owner, fettler, setting out on a journey

    Thank you all for very helpful input!

    The wiring on the bike, complicated to start with - everything seems to connect to everything else - plus modified and hacked about over the years, has defied my efforts at comprehension. Different approach required.

    Have spent this afternoon modifying the simplified wiring diagram Jim pointed out. Added the Boyer ignition and flashers. Now it feels we're getting somewhere.

    The bike has a 4-fuse box, and the simplified diagram uses that, so will go with 4 fuses.

    Pete, I decided to retain the safety relay for exactly those reasons. It seems to use the yellow wire - cloth covered on my XS - next to the alternator wiring. Does anybody know what this wire is or does? Does it tell the relay the that alternator is running?

    But my other remaining question (for now . . . ) concerns the solenoid. This has the main +ve feed from the battery, which also goes on to the ignition switch. Also, the blue/white signal from the starter button via SSR. And there may need to be one more, but I cannot figure out what this needs to be.

    For what it's worth, a picture of my first rough draft of the simplified scheme:


    PICT1972.JPG

    The tracer wire, Japanese 3.9 mm bullet connectors and various other bits and bobs arrived today, so the plan is to start cutting and joining wires tomorrow.

    It's Christmas soon?
     
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  16. 5twins

    5twins XS650 Guru Top Contributor

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    The yellow wire from the alternator feeds a voltage signal to the safety relay to trip it once the bike starts and the alternator starts producing. You need it. It's what makes the safety relay work.
     
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  17. 5twins

    5twins XS650 Guru Top Contributor

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    The solenoid is a heavy duty relay or switch that acts upon the heavy battery cable that effectively passes through it. Tripping the relay lets battery power flow through to the starter motor. There are two smaller wires connected to it, a red/white and a blue/white. These are what "flip the switch" or trigger the relay. The red/white comes from the safety relay. The safety relay controls power out on it depending whether the motor is running or not. Not running, power is allowed to flow out. Running, the power is cut. This is the safety relay's function, to stop the starter from working if the motor is running. The blue/white is from the start button. It should run just directly to the solenoid, not to the safety relay at all. Pushing the start button grounds this wire out, completing the circuit between it and the red/white wire. That trips the relay (solenoid) and lets power flow through on the big cable.
     
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  18. 5twins

    5twins XS650 Guru Top Contributor

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    When you get around to wiring up the lights, you're going to find that the tail light is powered right from the ignition switch. You have no on-off control over it. When the key is on, it is on. OK, so you're thinking no big deal, just clip the blue tail light wire from the ignition switch and run it off the headlight on-off switch. Well, that would work but you'd lose the parking light feature, which while I don't use it much, I think it's nice to have. There is a better way. If you examine the bottom of the switch plate in the ignition switch where the wires connect, you'll find the blue wire connected in two spots. The first connection along with a red wire is the "Park" position. Then the blue is jumpered over to another connection point grouped with the red again and a brown. This is the "On" position. Clip that blue jumper wire outta there and the tail light will only come on in the "Park" position. Down at the 3 wire plug for the ignition switch, you'll need to pigtail off the blue so you can tie it into your headlight on-off switch .....

    [​IMG]
     
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  19. Raymondo

    Raymondo XS650 owner, fettler, setting out on a journey

    5t, much indebted, Sir! You have clarified most of my areas of doubt.

    As I suspected, the yellow wire activates the safety relay. I need to modify diagram so blue/white wire from solenoid goes directly to Start button and I need to connect red/wire from solenoid to safety relay.

    Looking at the simplified diagram, I realised that blue from Ignition is just for the Park function. I might simply disregard this - thinking back over a long career of riding motorbikes, I cannot remember ever using parking lights. I never park a bike in town at night on a public road. Concerned abut running the battery down but more concerned about people fiddling with or even nicking the bike!

    So having the taillight tied in with the headlamp is fine. Headlamp will be on when we are in motion pretty much all the time. But thank you for showing a better way to deal with the issue!

    Now to go and have a look at the bike and start figuring out what wires need to run where. Flashers are scheduled to be a last job - the cabling is dodgy and soldering new onto the tiny bulb holders in those mini-flashers will be a fiddly job.

    Incidentally, I've noticed in US you use indicators to mean the warning lights, in UK we call the flashers indicators because you are indicating your intentions to other road users. Not that you rely on them taking any notice . . .
     
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  20. MaxPete

    MaxPete Life with Lucille...I suggest, she decides. Top Contributor XS650.com Supporter

    Two continents.....separated by a language.
     
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