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1976 xs650c project from Ireland

Discussion in 'The Garage' started by beano, Aug 18, 2018.

  1. 5twins

    5twins XS650 Guru Top Contributor

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    Did you measure through the plug cap or just on the plug wire? If using 5K ohm caps, that would be added to the 8K ohm coil value for a total of around 13K. Yes, it should spark with that. The original caps were rated at an oddball 8 or 9K ohms so the total with them would be even higher, and the bikes ran.

    Are you sure that aftermarket ignition is wired in correctly?
     
    mrtwowheel likes this.
  2. beano

    beano XS650 Enthusiast

    Ok that makes sense, I measured it through the plug caps and they’re 5k plug caps so that 13k value is spot on.

    It must be the ignition unit so??
     
  3. 5twins

    5twins XS650 Guru Top Contributor

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    Could be, or the unit may be wired incorrectly. I thought you had pics of the coil connections and I thought something looked off. I thought I saw orange and grey leads connected together in one spot.
     
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  4. DaveO

    DaveO XS650 Addict

    Hi @beano

    Welcome to the forum.

    I see you had the coils off and cleaned up the contacts and you've also tested them with a multimeter. In theory they are good. But have you tried bench testing them? By this I mean running a couple of wires direct from the battery and then making and breaking the connection. (Make sure the spark plug is earthed against the fins).

    We don't know if the electronic ignition is still good and is wired up correctly, but all any ignition system does is break the power to the coils at the appropriate time. You can mimic this action with a couple of pieces of wire.

    Dave
     
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  5. DaveO

    DaveO XS650 Addict

    like this

     
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  6. beano

    beano XS650 Enthusiast

    yes i removed some pictures from an earlier post because i didnt want to be asking too many questions at the same time.

    i have the coils wired up as follows, please note photo was taken from the LHS with the RHS coil in my hand.

    [​IMG]


    yes there is an orange wire connecting from one coil into the grey wire to the ignition unit, now i may very well be wrong but this seems to correlate to the wiring diagram supplied with the ignition unit..................which itself may very well be wrong.

    [​IMG]

    here is a link to a pdf of the full installation instructions if anyone wishes to have a look.

    http://autocar-electrical.co.uk/products/newtronic-ignitions/yamaha/ckt-yam6

    Edit: i have also come across this link which seems to indicate a problem with the supplied wiring diagram.

    http://www.xs650.org.au/Technical Info/Ignition.htm
     
    Last edited: Aug 25, 2018
  7. 5twins

    5twins XS650 Guru Top Contributor

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    Your coil wiring looks correct. Even though many of the stock wiring diagrams show a gray wire coming out of one coil, orange wire coming out of the other, I've only seen these stock coils with orange wires on them. That Australian web page is rather vague, not to mention the terrible, blurry pics, lol. I'd feel stupid even posting a pic that bad. I guess the only way you could find out what he actually did would be to contact him. But good luck with that, the posting is very old I think.

    I think the wiring diagram you have looks correct. I don't see what could be done differently. I'd run those simple coil tests DaveO outlined.
     
  8. DaveO

    DaveO XS650 Addict

    I think the statement "Again I found faults. The wiring diagram is incorrect and I had to swap over the coil wiring, to make the bike run." from xs650.org.au is maybe a bit of a read herring." Perhaps he hadn't labelled the coils "RHS" and "LHS" as you have. (Does it even matter? I don't know.)

    If its any help with orange wire / grey wire conundrum when I took my standard stuff off moons ago to fit a Boyer I wasn't very confident with my electrical skills (not much has changed) so I made a diagram in case I wanted to put it all back. If its any help here it is.

    IMG_2144.JPG
    It shows both coils having brown (power) and orange (back to the points). One goes via a red and wire one via a grey wire. I think your wiring is might be OK but we can't see all of it. You said you'd heard it running. But there's something funky going on here …

    funky.JPG

    Maybe a short?

    I'd bench test the coils. If you can get a spark out of them. I bet you can. You'll have eliminated half of the system as being the source of the problem. Then we can start back on the Newtronics stuff.

    I bet their documentation is right .. but its not very clear I must admit.
     
  9. 5twins

    5twins XS650 Guru Top Contributor

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    I think their wiring diagram is much clearer than that Aussie site's info, lol.
     
    DaveO likes this.
  10. beano

    beano XS650 Enthusiast

    Thank you so much for all your efforts @DaveO @5twins @MaxPete i have good news to report........we have spark!!

    I was feeling pretty confident about the coils after the results of the testing earlier so turned my attention to the wiring on the newtronic.

    after a few minutes of staring at things i wasn’t very happy with the way the ground wire from the ignition unit was earthed (to the top of the airbox)

    so I unscrewed it and attached it to the negative from the battery and voila, plenty of glorious beautiful sparks.

    Once again thanks to all for the great advive above, it really sped up the process, hoping to hear her run tomorrow fingers crossed.
     
  11. DaveO

    DaveO XS650 Addict

  12. DaveO

    DaveO XS650 Addict

    black wire.JPG

    And there's the black earth wire just as @5twins said it should be.
     
  13. 5twins

    5twins XS650 Guru Top Contributor

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    On the original harness, that is a very important ground wire. It doesn't have anything to do with the coils really but it is the main ground wire and ground connection for practically everything else in the harness that needs a ground. I moved mine over to the right coil mount because I needed that left side for my Pamco ground.

    [​IMG]
     
  14. MaxPete

    MaxPete New knee installed but still breakin’ her in.... Top Contributor XS650.com Supporter

    Yeah, the airbox wouldn’t be very good because for one thing, it is all painted and that paint is an insulator plus, it is at least partially attached to the battery box which is suspended on those four big diameter rubber isolators that keep the battery from being shaken to death.

    Anyhow, as 5Twins stated - ground (aka earth) connections are very important and as several other people around here have pointed out before - “these bikes vibrate a bit you know”. ;)
     
    Last edited: Aug 26, 2018
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  15. beano

    beano XS650 Enthusiast

    update time

    removed the carbs to give them a clean etc, they were pretty dirty and gummed up.

    [​IMG]

    [​IMG]

    the main jet was butchered but with a bit of patience and some heat and penetrating fluid i managed to get it out and replaced it with a new one.

    [​IMG]

    [​IMG]

    [​IMG]

    it took a couple of hours but i managed to get them pretty clean in the end, its amazing what you can do with a can of of carb cleaner, a paintbrush, a toothbrush and some compressed air!!

    [​IMG]

    then i set the mixture screws and the the float heights to spec and re mounted them, all good to go.


    so i switched on the ignition and went to give her a kick and received the most violent kickback of my entire life!! after rolling around on the ground for a few minutes and checking that my ankle wasnt broke i came to the conclusion it must have something to do with the advance mechanism??

    i swapped over the plug leads to see if i maybe wired the coils backwards but while there was now no kickback there was only some small backfires.

    im thinking maybe pull the rotor from the advance mechanism and start again?? must find that timing light..............
     
    Last edited: Aug 26, 2018
  16. MaxPete

    MaxPete New knee installed but still breakin’ her in.... Top Contributor XS650.com Supporter

    Well, you’re making progress at least Beano. I like that wooden box you are using for the carb parts!


    Pete
     
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  17. 5twins

    5twins XS650 Guru Top Contributor

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    Check the advance unit and advance rod running through the cam. They get all crusty and rusty then don't function as they should. Both need to be kept clean and lubed up. A quick test is to rotate the advance rod by hand on the advance side, until the weights spread out, then release. It should snap the weights back in smartly.
     
  18. beano

    beano XS650 Enthusiast


    thanks, its a bit overkill for the xs carbs as they're quite simple, but i have it so might as well use it. i made it originally for my fzr carbs which have different components, jets, needles etc for different cylinders, handy to have when you have it all stripped and are waiting a few weeks for parts, no need to remember where anything goes!!

    [​IMG]


    yes i will check all that and pull the advance rod some evening this week, have never worked on a bike with points before so will do some reading up on it before i go at it. i need to step away from it for a day or two anyway before i set it on fire!!
     
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  19. Paul Sutton

    Paul Sutton Silent but Deadly Top Contributor

    Beano, great photos of the bike! I would never have imagined just how much a bike can change with time. Did your Father own this from new? Good move getting a new harness. By the time you mess with and clean up an old harness you end up wishing you had bought a new one. The only issue is that sometimes the new harness has some little variations that can get frustrating to sort. But all your connectors will be shiny, new and trouble free..
     
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  20. 5twins

    5twins XS650 Guru Top Contributor

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    Yes, the advance unit and advance rod are two of the most neglected items on these bikes. They were lubed up when the factory assembled them many years ago and most have never been touched since, lol. Even though none of the manuals mention them, keeping them lubed should be considered a maintenance item. It doesn't need doing often, maybe every couple of years, but it does need doing.
     
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