Kill switch wiring

Discussion in 'Norm's 2 stroke repair center' started by rslavicek, May 11, 2009.

  1. rslavicek

    rslavicek New Member

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    I'm finishing up my first build and as usual confused buy the chinese-english translations. My instructions tell me to hook up the white wire coming off the engine to the yellow wire on the kill switch but make no mention of the green wire coming from the kill switch. My best guess is that it's a ground and needs to be connected to the engine, but someone put a plastic sleve over it, which got me wondering if I should just not attach it. Would appreciate any help you can come up with. Worst case I will go with my gut and if it blows tha magneto then I have another project.

    2Door has the way I do it to wire up the engine. you can get by with just one wire to the engines blue cdi wire and one to a ground(frame or engine or the black wire). The black wire from the engine to the cdi is a ground. Some kill switches only have one wire. 2 wire kill switches either wire from the kill switch to the blue on the cdi and one to a frame ground will work. I leave the white wire for a light. if your not using a light cap off the wire. Best bet is use the diagram the 2Door has.
    Norman
     
    #1 rslavicek, May 11, 2009
    Last edited by a moderator: May 11, 2009
  2. Echotraveler

    Echotraveler New Member

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    ok heres how i was told/did/do

    theres 3 wires coming from the motor
    *the white is only for the light
    and other 2 (this to go to the spark)


    what do i do with the 2 wires coming from the kill switch

    its so simple, one could get confused...one of the cables of the "kill switch" gos to one "wire of the spark" and the other "kill switch wire" to the other "spark wire".


    whats difficult to explane/understand, is that you still connect the "motor wires" to the cdi and also the "killswitch wires".

    you end up with 2 x 3wire union
     
  3. 2door

    2door Moderator
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    Try it this way. It will work just fine. Promise.
    Tom
     

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  4. rslavicek

    rslavicek New Member

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    Thanks all. I will go ahead and follow your advice. Has anyone found a way to shorten the throttle cable. Mine seems to work but it sticke out over the front wheel and looks sloppy. I'm taking it slow, I've been waiting for a sprocket adapter and making modifications as I go.
     
  5. Echotraveler

    Echotraveler New Member

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    the long throtle cable would be more aesthetic...some tight wrap should at least let you fine tune the MB...

    to shorten it you would need the end caps for the cable....maybe someone can shime in on that.
     
  6. Norman

    Norman LORD VADER Moderator
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    #6 Norman, May 11, 2009
    Last edited: May 11, 2009
  7. joeblow

    joeblow New Member

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    I have a 2 wire kill switch and I am having trouble understanding how this works.

    The diagram shows a splice in the engine ignition that will stop the current and stall the engine. I get that one.

    The other way to do it is the way mine is instructing me to do it, by attaching the yellow wire to the white engine wire and ground the green. I did this and it failed. I believe the ground was poorly grounded and I will try again. If it does not work I am worried I cannot splice the black and blue wires, as they are very short. I would have to cut off the little connector bits installed and get some three way connectors, but I would also have to move my cdi closer (very close) to my muffler.

    I also do not understand how this ground system works. If the switch is open and pushing it closes it, then how is it not constantly grounding itself? It seems like this switch has to be a closed switch and opening it sends the current into the frame to short the magneto. If this is true I don't see how the alternate wiring system can work. would I need a new switch?

    please help me on this, I don't want my second ride to be the unstoppable top speed death roll the last one was. I think I figured out the carb now, thanks to the help of this forum, but I would like to be safer next time. thank god for brakes.
     
  8. 2door

    2door Moderator
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    Let me see if I can make this simple and understandable for you. The kill switch is a simple, normally open contact, called a momentary switch. When you push it it connects the two wires connected to it together. The black wire from your engine is a ground. It is connected directly to the engine case inside the magneto cover. The blue wire carries a pulsed current to the CDI (coil) and the black wire completes that circuit. By connecting your wiring as in the diagram I posted above what you do is ground out the blue wire when you push the kill button. The same thing can be accomplished by grounding the white wire to the engine or bike frame if the engine is attached to it in such a way as to allow an electrical connection (no paint, rust, rubber etc). The white wire however is provided as a power source for a small light bulb (headlight/tailight). If you elect to use the white wire to one of the kill switch wires then the other kill switch wire will need to be attached to preferably the engine case or the bike frame if there is good metal to metal contact. I hope this clears the wiring issue up for you. If you have doubts about my advice remove the magneto cover and look at the wiring for yourself.
    Tom
     
    #8 2door, May 12, 2009
    Last edited: May 19, 2009
  9. joeblow

    joeblow New Member

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    I have no doubts 2door, and that was a lovely explanation. thank you.
     
  10. bikenerd

    bikenerd New Member

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    I hope to revive this old thread. I hooked up my kill switch per instructions, black and blue motor to corresponding black and blue CDI wires, white motor to red/yellow kill switch wire, green kill switch wire to ground on frame. First ten hours of operation everything worked perfectly. Last two hours of operation the kill switch became sluggish, taking 10 to 15 seconds to kill the engine as it slowly lost rpms. Then it wouldn't run at all unless I keep the kill switch depressed which causes it to run just fine. My ohm meter says the kill switch is still operating correctly as a temporary closed switch, infinitie resistance when untouched and zero resistance when depressed. I tried various combinations of switching connections but the only one that works is leaving motor and cdi hooked up black/black and blue/blue and grounding the white wire. I don't understand what's changed or what I should do about it. I suppose I could replace the kill switch with a temporary open switch but doing things without understanding what's happening makes me uneasy. Any ideas?
     
  11. Norman

    Norman LORD VADER Moderator
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    If I understand right? You say that to make the engine run you now have to ground the white wire?
    If that is the case then the ground wire on the mag coil has broken. You can resolder the bare copper wire to the mag coil to fix the problem.
    Take the mag coil off of the engine. look at the frame of the coil you should see a bare copper wire soldered to the frame this wire is around a 26 gauge in size which is a single strand wire and its small in size. Some times this wire isn't soldered on very well. resolder it and give the engine a try, leave the white wire unconnected to anything.
    If you have a ohm meter you can test the mag coil.
    put one lead of the ohm meter on the frame of the mag coil the other lead on the blue wire you should see around 300 or more ohms.
    then put the meter on the white wire and the other lead still on the coils frame you should see around 2 to 2.5 ohms.
    if you get no reading from either blue or white wire to the mag coils frame then the ground on the mag coil ground wire is bad( remember this wire is very small and hard to see it is a single strand wire ) and you will be able to repair it by soldering it back.
    with the meter attached one lead to the blue and one lead to the white you will get a reading around 290 or more it will be the combined total of the two leads or close to it.
     
  12. bikenerd

    bikenerd New Member

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    Norm,
    Thanks for you swift reply. I checked the ground wire coming out of the center of the magneto coil which is soldered to the magneto bracket. When I touch the wire where it exits the coil, and the magneto bracket, with my ohmeter it shows no resistance. I even attempted to push the wire around with a toothpick while testing but the needle didn't move. It feels tight. Blue wire to magneto bracket shows infinite resistance, ditto white to magneto bracket. White to blue shows .4 ohms. I had to gently file off the insulating lacquer in a couple of places to do the testing. Maybe it's time to replace the magneto?
     
  13. mwsbrewn

    mwsbrewn New Member

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    Hello Tom. Sorry to beat a dead horse.
    I hook up my wires just as you say and as your picture shows.
    white caped.
    blue to blue, yellow
    black to black, green

    And nothing....
    my kill switch will not work. Also funny, when I come to a stop, I press in the clutch and my motor dies. Isnt it suppost to idle instead? What am I doing wrong? Thanks
    Michael
     
  14. 2door

    2door Moderator
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    mwsbrewn,
    Do you have an ohm meter? If so disconnect the kill switch and put your meter leads on the wires from the switch. With the button depressed you should read no resistance, or full scale meter reading. When you release the button you should see no reading on the meter. (open circuit). Anything else and your kill switch is defective. I've repaired a couple of bad switches. My advice, pick up a new one which means a new throttle grip too because most are a single assembly. It could be a bad/broken wire so you'd need to ohm out the wires to the switch to rule that out.
    As far as your idle, if it idles too slow and dies then adjust the idle speed screw. In increases idle speed, out decreases it. That's assuming you have either an NT or a Dax, RT carb. I'm not sure about the infamous CRS carb. Someone else will chime in about that beast.
    Tom
     
    #14 2door, Oct 17, 2011
    Last edited: Oct 17, 2011
  15. maintenancenazi

    maintenancenazi New Member

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    Very good information 2 door, thank you for posting it. I know I will be learning allot of details on these engines here! And a big thanks to Norman as well!!
     

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