1985 Honda ATC70 weak/no spark

Thread: 1985 Honda ATC70 weak/no spark

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  1. HoldMyBeer said:

    1985 Honda ATC70 weak/no spark

    Not an electrical guy and going nuts here. 1985 ATC 70 been sitting for a few years. Replaced plug wire/coil, condensor, points, stator coils, cleaned flywheel magnets/stator enclosure, set point gap to 0.14, NGK plug set to 0.28. Getting fuel, getting air, have compression. No or weak spark. Plug doesn't fire but I can stick a screw driver in the plug wire and get a weak spark occasionally. Bought a Spangler 70 stator rebuild kit and nearly had a stroke after it still didn't fire. No lights installed. One wire going from the kill switch to the engine and one wire coming of the ignition coil tied to it going into one and plugging in the wiring harness. Any ideas appreciated, I'm at a loss. Thanks
     
  2. Kingcricket said:
    Probably you neutral switch in your gear box
     
  3. HoldMyBeer said:
    First, thank you very much for the reply. This is driving me crazy. Are we talking about pulling the side case off in that scenario? I shifted from neutral to first a few (literal) hundred times and the indicator sticking out of the case moves freely. The green wire with the stripe is plugged into the spring clip and deadheads at a male connector in my harness. Do I ground it at the other end? Bypass it somehow? The Spangler stator kit didn't come with that green striped safety switch wire so I pulled the old one out and threaded in my new components. Doesn't look like it does anything but obviously it has some purpose... I'm not finding much documentation on the switch other than people saying they can be a problem
     
  4. Kingcricket said:
    There should a a contact inside the case that grounds when in neutral I believe. Should be able to ground The wire on the wiring harness that went to the switch.

    Just going by what diagram I see, this is mainly an issue with the trx 70 but just figured give it a shot. Other than that did you make sure you points gap is in time with your F mark on the flywheel. Timing is real important.
    Last edited by Kingcricket; 07-31-2016 at 05:15 PM.
     
  5. HoldMyBeer said:
    I grounded the wire coming from the safety switch and weak spark either way, not enough to fire the plug. I'll recheck the points tomorrow (later today at this point) and repost what worked. It has to be something easy and I'm not seeing it. Gotta love it or you'd burn it and roast marshmallows on the fire
     
  6. HoldMyBeer said:
    I'll have to look at it and process that a bit. 3 wires in the harness, 2 from the coil and 1 from the condenser if I'm thinking right. 1 runs to the kill switch, the other 2 deadhead into an unused plug. I added the wire from the safety switch and deadheaded it into the plug just because the old one was that way. Have to research what I'm looking at, electrical isn't my thing but at this rate it will be. I'll post some results after I try that out. Thank you
     
  7. wonderboy's Avatar

    wonderboy said:
    Assuming you have the wiring correct, my suggestion is to check the timing. In my experience, just setting the point gap isn't enough. You really should check the timing. The manual shows a real simple way to use a test light to check your timing. Page 3-4 and 3-5 show how to use the light and how to tweak the point gap with a screwdriver (there are slots in the castings around the points that make this pretty easy with a large flatblade).

    This process will have the added benefit of confirming if your wiring is ok.

    Bottom line regarding the wiring: There really only needs to be one wire connected for the engine to fire: points to coil. The only purpose of the kill switch is to ground out this wire to shut the motor down. So if you really wanted to go bare bones (without the ability to shut the motor off) just unplug the kill switch for now and just make sure you have the black wire from the points going to the primary side of the coil. Make sure that the coil is able to ground to the frame cleanly, since the ground connection is required to complete the circuit to the motor.
    - Frank

    1984 200ES Big Red
    1985 350X (x2)
    1986 350X
    1986 250SX
    1984 Auto-X
    1984 ATC70
    1985 ATC70
     
  8. coolpool's Avatar

    coolpool said:
    I'm with wonder boy on this. Also confirm that your key way isn't partially sheared. That can cause a whole other world of issues.

    Note: There is no neutral safety switch on these.
    Trikes
    1970/71 US 90 (Aquarius Blue)
    1970/71 US 90 (Future Project)
    1972/73 US 90 Camo Project (110 Big Bore)
    1972/73 US 90 Green
    1982 ATC 70
    1983 ATC 70 (Ladybug)
    1973 ATC 70

    1965 Marketeer 3 Wheel Golf Cart with 1986 Honda 250 drivetrain

    TF 2015

    Other
    1983 Honda Z50

    Feedback http://www.3wheelerworld.com/showthr...ck-for-coopool
    http://www.3wheelerworld.com/showthr...k-for-coolpool
     
  9. HoldMyBeer said:
    Keyway is fine. Neutral safety switch is working (even if it does nothing it works as it should) and timing seems correct. I'm thinking its a ground issue of some sort. Used a meter to check when points open and close and it moves as I spin the flywheel but it show continuity in all positions. Even when the points are visibly full open.
     
  10. gimmeamidget said:
    unplug both wires going to kill switch just for fun....should start without switch but wont shut off.
     
  11. HoldMyBeer said:
    The points show closed at all times with a meter unless I unbolt the lower coil under the flywheel from the engine case. Unbolt the lower coil but leave it hooked to the condenser and points show open and closed as they should.
     
  12. Kingcricket said:
    Maybe get some pics up of everything if you can.

    Cause if everything is brand new it has to be a bad ground or timing.

    Check this video
    https://www.google.com/url?sa=t&sour...y5zVwtpUfRGxRA
    Last edited by Kingcricket; 08-03-2016 at 08:31 PM. Reason: Added link
     
  13. HoldMyBeer said:
    I'm agreeing. Ground or timing. Hope pictures attach. The continuity issue with the points make me think ground although I've seen some people saying condenser. Keep in mind what I've tried, not to say I haven't missed something. I've been through 3 condensers, 3 new sets of points and two new stator coils complete with a wiring harness. Only 3 wires come into play. Condenser to IGN coil, stator coils to condenser. With a meter the only time I can see a break in continuity is when the points open is when the lower coil is disconnected. I leave the coil itself soldered to the condenser but I unscrew the lower coil and lift it off the case and like magic continuity breaks when the points are open. With the point gap at 0.014 and the flywheel on the "T" I can get weak spark but not fire the plug. And believe me I've set and set the points. Tight, large different places between the "F" and "T" mark. It has to be such a simple issue that I don't see or don't comprehend. It has to be... Click image for larger version. 

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  14. Kingcricket said:
    Your continuity is going through your condenser. One side of your points are hooked to that and the other is grounded, so when you disconnect your lower coil you loose that ground to your coil which is also hooked to the condenser I believe
     
  15. HoldMyBeer said:
    I woke up this morning and I think it clicked in my head. Between the video link and an old post mentioning the condenser always showing ground it has to be timing. I've disregarded a test light because there is no battery but I'll use one off something else later to set the time and see Maybe a feeler gauge alone isn't enough. Thanks Kingcricket, that video may have been what made me understand what's happening