How does the killswitch work?

Discussion in 'Motorized Bicycle General Discussion' started by Dougan, May 27, 2010.

  1. Dougan

    Dougan New Member

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    I have the skyhawk 66cc GT5 kit. Almost done!

    Anyway, got the throttle installed and stuff. It has a yellow killswitch on the throttle grip. It has a green and a yellow wire coming from it. It looks like the yellow wire connects to the white wire coming out of the CDI. The green wire has a circle tip on it, like a ground wire would look like on something you were installing on your car.

    The instructions say "OPTIONAL NEW STYLE THROTTLE with kill switch: one wire goes to white wire from engine and other to frame grd"

    Seems pretty direct in telling me i have to ground the green wire to the frame of my bike. But why? How does that do anything?
     
  2. Venice Motor Bikes

    Venice Motor Bikes Custom Builder / Dealer/Los Angeles

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    Don't use the kill button!! cut off the wires & use the clutch (or choke) to stall it & shut it off.
    Sometimes the kill button burns up the mag/coil. (usually when you're 10 miles from home.) :(
     
  3. Dougan

    Dougan New Member

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    if I just don't rig it up and leave that white wire loose (open part covered w/ electrical tape, of course) will I still run? I'm not really sure hwo the CDI works and I'm not sure if I'll be breaking the circuit by not installing the killswitch.
     
  4. oldtimer54

    oldtimer54 Member

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    It will run fine with out the kill switch hooked up.
     
  5. bairdco

    bairdco a guy who makes cool bikes

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    as long as the white wire doesn't short out it'll run fine. the other two wires are for the CDI.

    if you don't run the switch i recommend heat shrinking the end of the white wire, then slip a larger piece over all three wires and heat shrink them together. that way the white wire's hidden and protected.

    if you don't run the kill switch, you can use the clutch to kill it when you're stopped or barely moving, or flip the choke lever up while you're riding to choke it out.
     
  6. GearNut

    GearNut Active Member

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    The stock kill switch shorts out the signal from the mag to engine ground.
    IMHO, if any switch really needs to be used, it should be an on/off toggle switch in line with the blue wire. That way you are just disconnecting the signal going to the CDI unit rather than shorting out a component.
     
  7. dag_29307

    dag_29307 New Member

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    Are kill switches really that bad? I just keep my idle really low so when I stop my engine just dies. I have to pedal to start moving anyways. But I am intrigued by this new information. So could I use the kill switch and wire to power a horn? I already have lights so I would love to add a horn if possible. I wanna get one that sounds like the road runner, I just couldn't figure how to wire the switch in.
     
  8. oldtimer54

    oldtimer54 Member

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    Great idea dag. Iam not sure how much power a horn takes? Do you guys in the know think the white wire has enough power to run a horn?
     
  9. TerrontheSnake

    TerrontheSnake New Member

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    Every kill switch on every small motor I have worked on uses a short circuit type switch. I have never had an issue using mine, but it seems some here have had bad experiences. I even used mine as a "down shift" by holding at speed to slow a little into a corner. Never burnt up, no issues with it at all actually.
     
  10. Venice Motor Bikes

    Venice Motor Bikes Custom Builder / Dealer/Los Angeles

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    I'll add this note... I've seen many mag/coils short out for one reason or another; but I've never had one short out that had the kill button disconnected!
     
  11. GearNut

    GearNut Active Member

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    On a points style ignition the kill switch or button method of grounding the signal to chassis ground was and still is perfectly acceptable.
    Quite a few of the more robust modern electronic ignitions can also withstand this method.
    I would not venture so far as to call the ignitions used in these HT engines robust, more like barely adequate and cheaply made.
    Do as you wish, but consider the quality of what you are working with and how most electronics respond to being repeatedly shorted out.
     

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