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1981 No Spark, Tried everything Ive read...Please Help!

Discussion in 'The Garage' started by specialman, Mar 27, 2011.

  1. specialman

    specialman XS Power

    I tried literally everything, but im sure you guys can narrow it down maybe a little bit further but im stuck and lost and im to the point where im about the rip the whole harness out and make a simplified wiring like i did with my 72.:yikes::banghead:

    Ok, first off to make things easier I made jumpers to connect the ignition switch. (red, brown, blue) Then i made jumpers to also eliminate the kill switch (red to red)

    I then got power to all I think 5 fuses with good voltage. So i tested the Coil (red/white stripe to orange) i got somewhere in between 2.5-3 ohm. Then i tested one lead end to the other without resister caps on I will post exact reading in a couple hours im going out to test everything one more time. I think it was like 11-13 ohms if i remember correctly.

    Ok then i tested the pre-coil (inside shifter side case) well i didnt want to stab holes in the wires so i brought up the wiring diagram found out those three wires (which strangely change colors. Where they come out of the unit i think they are black, grey, orange then in the harness plug for the cdi they are green/white black and red but i figured out which ones where which:thumbsup:) I tested black to red and black to green i got a little under .700 for the one (i think like .697) and a little over .700 for the other.
    I dont know what else to test if someone has some idea(s) that would be great but if i cant get this thing figured out soon, im ditching the whole harness and making a simplified one.

    A little history on this bike i bought it stock 2 yrs ago (ran great) last yr i sold it to a guy and he cut the frame and in general just f'd this thing up (without even riding it)
    Then told me he couldnt get any spark. When i got it back he had the grounding strap on the opposing side of where the positive goes on the starter selonoid. But he didnt have any battery in it. I immediately fixed that once i got that home and i have been tinkering around on it since but it has me :yikes: right now this bike has less than 10k miles on it, i just dont see any resonable explanation for this thing not having spark.

    I just want to :bike:
  2. From what you are say its a stock bike with stock harness correct!
    Get a test light or volt/ohm meter and see if you have 12 volts to coil and to TCI unit.
    No 12 volts then something not hooked up. There are only a couple wires that have to be hooked up to get spark. Here is a diagram that may help you a little. Its for a chopper but close to same and if all the wires are screwed up anyhow just follow this and you will have 12 volts and if all the parts are good spark. You have TCI black box and REG/REC correct.

    Attached Files:

  3. gggGary

    gggGary Cara Mia!!

    Did he weld on the bike?? :banghead: :( :doh: :mad:
    Hope the TCI didn't get smoked if he did.
  4. specialman

    specialman XS Power

    yes this is correct! I will test them in a little bit. I have the battery back on the charger right now.
  5. specialman

    specialman XS Power

    i have 2 "tci" units to test and try with.
  6. littlebill31

    littlebill31 Smells of Raw Fuel

    How do you test for spark? I ask 'cuz pulling off a cap, as I have seen people do, without grounding the spark plug to the engine, can fry the TCI. Some just pull the plug and cap and look at the plug while they turn the engine or pull off the cap to tune by using the "dead cylinder" method. Can't do that with the TCI.
  7. specialman

    specialman XS Power

    i hold the threads of the plug to the heat sink fins on the cylinder. Is this not correct? Thanks in advance for any insite..
  8. littlebill31

    littlebill31 Smells of Raw Fuel

    Ya, holding it to the fins is fine. That's what you want to do so it, essentially, arcs. I mean that some don't and either just pull the boot or don't ground it. This is ok for points engines, a big no-no for TCI.
  9. gggGary

    gggGary Cara Mia!!

    grab about 2' of bare copper house wire, wrap an end around each plug let it touch the engine and you won't need three hands to keep everything from flopping around while you crank it over.
  10. If the bike still has the stock 4 position glass fuse type of fuseholders......................they are very unreliable......................replace with automotive blade type fuseholders. They can look good, but have high resistance, causing voltage drop to the ignition. The kill switch is another item that can cause voltage drops.

    Pick-up coils should be about 700 ohms. High voltage from lead to lead should be about 11K ohms, without resistance caps.
  11. None of you guys have a spark tester? You can get them at a lot of places. I think i got mine threw DENNIS KIRK. It goes between the plug and cap and shows the spark or you can just ground the plug when you take it out. I have never burned up a TCI testing spark you are only cranking motor for a couple seconds. If you don't see spark on first couple cranks there is none. They even sell spark plug caps that light up when they fire you could use those too. I just wouldn't do it without a good ground on after market ignitions because some of there directions say that you could burn up there unit.
  12. srinath

    srinath XS650 Enthusiast

    I am actually in the same situation, only worse off. Mine is an 81 with stock wiring but a lot of the relays etc removed and bypassed for the sake of eliminating bad relays.

    The ignition coil tests like he said, 11K ohm secondary, 3.2 ohm primary.
    The pickup's also test right @ 700.
    The thing started and ran a few mins ~2 weeks ago.
    Then I have not had spark for nearly 2 weeks. I intermittently got a weak spark but never got it to start.

    Then I pulled off the ignition box and opened it, man is it easy to open, and the egg shaped diodes that go bad - were already swapped out for nice cylindrical radioshack ones. That leaves that transistor. I picked up a tip 120 @ radioshack, but haven't installed it yet. However my question revolves around that transistor.

    I have a transistor tester that is supposed to respond in 1 position in the low drive mode and in 2 adjacent positions in the high drive. It also should ahve under 1% leakage and what not. The one in the board responds in 1 position in high and none in low. However it tests very good for leaks, nearly 0.

    Anyway I am thinking of putting in that tip120 just to look for spark. Or can anyone tell me what else could be going on.
  13. xjwmx

    xjwmx XS650 Guru

    ^Do the joints for the diodes look like the rest? They might be original, or somebody might have already thought it was bad and worked on it.

    Since the wiring has been changed, I'd get one of the simplified diagrams with TCI and check with a meter power, ground, pickup connections, and coil connections to the TCI. Tighten up and clean the connectors, etc. Also check the plug wires and caps. When you take the measurements, clip the leads on and move the wires around to try find an intermittent connection.
  14. specialman

    specialman XS Power

    i just picked up a $40 harbor freight special with a bunch of spools of different color wire. I am going to use the diagram above to re-wire it with basic needs. Wish me luck!
  15. XSLeo

    XSLeo XS650 Guru

    Some one found a bad zener diode in there TCI. If you look thru the threads about fixing the TCI boxes you will find it.
  16. xjwmx

    xjwmx XS650 Guru

    specialman, when I said check out a simplified wiring diagram, I meant to use it to check your voltages with (because it's much easier to read than the one in the manual). But rewiring it with it might not be a bad idea! If the po/pm messed it up and never rode it, no telling what its wiring's like now.

    Here's a thread on wiring that's current:

    Current, get it? Ha ha! Current. Ummmm never mind.
  17. specialman

    specialman XS Power

    lol thx i got spark but i need to clean up the carbs and sync them so this thing will stay running

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