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Seca650 No spark

Discussion in 'XJ Technical Chat' started by MrSeca, Apr 2, 2019.

  1. MrSeca

    MrSeca Member

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    Hi. I am the proud new owner of a Seca 650 and it's time for the restoration to begin. It's bone stock and It has 22,000 miles on it. It lived in Hawaii for most of it's life and then a second owner had it for about 3 years until I picked it up yesterday. Very excited.
    The engine turns over but I'm not getting spark. Ugh! The other two major problems are that the master cylinder needs to be rebuilt and the tank has rust in it.

    For now I'm concentrating on the no spark situation. When I bought it the PO believes that the resistance in the plug caps might be the culprit. I checked the primary and secondary side on the ignition coils just in case and it all measures out. I also checked the continuity of the fuse box at the ignition and that's fine (original fusebox). The battery is good, btw. I have to admit I haven't checked the pick-up coils yet. Being a bit new to bikes (one and a half years) I'm not exactly sure what a good cap should measure out to so I checked the resistance on each cap and this is what it came too. 1)5.89ohms, 2)9.45ohms, 3)4.65ohms, 4)9.84ohms. Do I need new caps? What other tests should I do?

    Also, if anyone has any good tutorials out there video or otherwise on how to clean and seal a gas tank that would be much appreciated. I guess I should mention that if there's also anything out there on how to rebuild the master cylinder that would also be appreciated.

    I'm happy to be part of this group and I look forward to your comments.

    Mr. Seca
     
  2. MrSeca

    MrSeca Member

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    Update: The pick-up coils measure at 629ohms and 646ohms.
     
  3. MrSeca

    MrSeca Member

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    One more update. I just wanted to compare the results of the ignition coils secondary side with and without the plug caps. Here's what I came up with
    #1 & #4 11.36k ohms
    /with caps: 30.79k
    #2 & #3 11.06k
    /with caps: 21.73k
     
  4. Simmy

    Simmy Well-Known Member

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    Love your handle
     
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  5. Rooster53

    Rooster53 Well-Known Member Premium Member

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    Welcome to XJbikes, the following link contains answers to many questions and is a must read to get your bike into a safe and reliable state:

    https://www.xjbikes.com/forums/threads/the-information-overload-hour.27544/

    From the above link:

    XJ650 models:

    Pick-up coils:
    1980-81 XJ650 Maxim and Midnight Maxim: 700 ohms +/- 20% = 560 ohms to 840 ohms acceptable range
    1982 XJ650RJ Seca (non-yics engines): 700 ohms +/- 20% = 560 ohms to 840 ohms acceptable range
    1982-84 XJ650 Maxim: 650 ohms +/- 20% = 520 ohms to 780 ohms acceptable range
    1982 XJ650RJC Seca (yics engine): 650 ohms +/- 20% = 520 ohms to 780 ohms acceptable range
    1982-83 XJ650 Turbo: 120 ohms +/- 20% = 96 ohms to 144 ohms acceptable range


    Ignition Coils:

    Primary side (input from main wiring harness):
    2.5 ohms +/- 10% = 2.25 ohms - 2.75 ohms acceptable range

    Secondary side (spark plug wires, without their end caps):
    11K ohms +/- 20% = 8,800 ohms - 13,200 ohms acceptable range


    Spark plug caps:
    5K +/- 20% = 4,000 to 6,000 ohms per cap acceptable range

    Spark plugs:
    0 ohms per plug

    So based on the reading you provided for the coils with caps it looks like the 1 and 4 caps have an issue - the first post somewhat contradicts that but I suspect a typo there. That said, none of the reading are high enough to prevent a spark so either something else is wrong or the methodology is wrong. One of the most common problems for a weak spark is a marginal battery. The battery should be checked with a load test by measuring the voltage to verify that the battery maintains at least 9.5 volts while the bike is cranking.
     
  6. MrSeca

    MrSeca Member

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    Thanks Rooster. You're right about the typo. I'll try the load test and go from there.
     
  7. Ryengoth

    Ryengoth Active Member Premium Member

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    You can also tag a larger 12V battery on for testing or put a 2/3A charger on the battery while it's cranking to rule out a battery issue.
     
  8. MrSeca

    MrSeca Member

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    Thanks Ryengoth. I was using the battery from my other bike but went ahead and purchased a brand new AGM since I needed a new one anyway.

    On further inspection I noticed an odd connection near the starter solenoid (see pic). I'm referring to the blue wire. Does this look right?
     

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  9. XJ550H

    XJ550H Well-Known Member Premium Member

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    the connector with the jumper wire is or looks like the solenoid connector from the harness. there should be a mating connector on the solenoid.
    what ever it is it shouldn't be


    what color are the wires on that connector should be blue/white and red/white

    is it black/yellow and blue/yellow?
     
    Last edited: Apr 3, 2019
  10. XJ550H

    XJ550H Well-Known Member Premium Member

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    21k ohms with caps is what you should have not 30k. caps should be 5k ohms each
     
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  11. MrSeca

    MrSeca Member

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    It is a plain black wire and a blue wire with a yellow stripe.
     
  12. MrSeca

    MrSeca Member

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    Here is a better pic.
     

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  13. MrSeca

    MrSeca Member

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    Just did a load test on the battery and it only goes down to 10.63 volts so that seems okay. That odd connection might be the culprit but I can't seem to figure out where it goes.
     
  14. Rooster53

    Rooster53 Well-Known Member Premium Member

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    I am guessing a bit but that looks like a L/Y and B wire which would make that the side stand switch connector. The PO likely installed the jumper to bypass a bad or suspected bad side stand safety switch.

    The safety system (side stand relay) can disable the TCI assembly so that there is no spark. Since the PO was futzing around with that you could try pulling the side stand relay (blue dot) to troubleshoot the no spark issue. Pulling the relay disables the ignition cutoff feature which is normally activated by engaging the side stand relay to open a set of normally closed contacts. The side stand relay normally can be energized with either the neutral switch or the side stand switch.

    Another option to disable the ignition cutoff for troubleshooting is to disconnect the B/W wire at the TCI (Ignition Module) six pin connector. If you locate the B/W wire and follow it there should be a single bullet connector that can be disconnected.
     
    Last edited: Apr 3, 2019
  15. k-moe

    k-moe Pie, Bacon, Bourbon. Moderator Premium Member

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    Agreed. The sidestand switch has a long lead that connects to the harness near the starter solenoid.
    The way it's been bypassed indicates the PO had no idea how to bypass it and have the TCI make sparks.
     
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  16. MrSeca

    MrSeca Member

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    Well, I tried to go to the sidestand and pull the relay switch but I don't see any visible wires coming from there. Is there a pic that I could see to find it's location? I also found the B/W wire at the TCI unit and followed it to the what I think is the bullet connector (see pic) If this is correct is there another way to bypass it. It looks crimped in there and looks like it would be a pain trying to put that back together after I take it apart.
     

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  17. XJ550H

    XJ550H Well-Known Member Premium Member

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    you will like this link
    The Ultimate Relay, Switch, Sensor, and Diodes Guide

    Sidestand (kickstand) relay (blue): behind the flasher relay, under the front of the tank.


    Flasher: near the steering headpipe, on right side frame rail, under the right side ignition coil.


    the side stand switch does hook to a black wire and a blue/yellow wire .

    Rooster53 and K-moe are correct about the jumpered connector being the side stand switch connection.

    there should be a black/white wire with a bullet connector coming from tci. if you disconnect that wire it will bypass the sidestand safety switch. try that first before going under tand for the sidestand relay
     
    Last edited: Apr 3, 2019
  18. MrSeca

    MrSeca Member

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    Here is a pic of the side stand. I'm guessing that whatever relay, switch, sensor or whatever it's called has been removed.
     

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  19. XJ550H

    XJ550H Well-Known Member Premium Member

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    correct the sidestand switch has been removed.

    you should consider replacing it. when circuit functions properly if you deploy the sidestand bike shuts off. if you do not have on the bike you could have a bad left turn incident

    sidestand switch
    sidestand switch.PNG
     
    Last edited: Apr 3, 2019
  20. MrSeca

    MrSeca Member

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    Is there a way to hack the bullet connector without taking it apart? I'm just trying to prevent more work in the future trying to crimp that bad boy back together.
     

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