Kill switch wiring question

Discussion in 'General Questions' started by bikejock, May 15, 2015.

  1. bikejock

    bikejock Member

    I'm about to wire up my 4 stroke motor to the kill switch on my bike for an engine test. I got the green wire hooked up but whats weird is the kill switch in my kit came with a green wire and a red & yellow wire with a ring on the end. Should I just cut the ring off the end of the yellow and red and hook it up to the black wire? Or does it bolt on somewhere on the motor? 014.jpg

  2. jaguar

    jaguar Well-Known Member

    use your ohm-meter to see if the yellow wire is equal to the metal of the motor.
    If not then it wants a "floating" kill switch.
    A normal kill switch shorts one wire to chassis ground.
  3. bikejock

    bikejock Member

    So the yellow & red wire with the ring on the end is the ground for the kill switch button? My engine is a 49cc HS 142F built in mid 2014. Also I noticed it didn't have the red on/off switch other HS motors have. That's not going to be a problem as long as I ground that yellow and red wire, right?

    The directions that came with my kit seem to be a bit miss leading & somewhat confusing because it might be describing the wiring for a different motor. Who ever came up with these directions didn't do a good job. I've actually got more help at this forum and YouTube so far and go back to the directions for quick reference with some steps.
  4. The_Aleman

    The_Aleman Active Member

    The wire with the ring connector gets bolted to the engine, it does supply the ground.
  5. bikejock

    bikejock Member

    OK I hooked up that yellow and red wire with the ring on the end to a bolt on the transmission to avoid heat exposure from the engine so the engine doesn't melt the wire. Does this look OK?

    002.jpg 003.jpg
  6. The_Aleman

    The_Aleman Active Member

    You can bolt the ground to any screw on the engine itself; what you've done will work, but I recommend securing it out of sight.
  7. bikejock

    bikejock Member

    Thanks for the help. This is for an engine test anyway. I'll probably move the wire so it's out of sight before the first ride. I'm going to take a Jerry can to the gas station tomorrow to fill her up for the first time. I want to test the engine, throttle & kill switch and make sure everything runs smoothly before hooking up the chain to the rear wheel.

    Its going to be a few weeks before I take it on an actual test drive on the road. I'm still saving up for a special 3 piece wide crank axle so I can use my original bearings and chain ring for the pedal crank. The chain ring that came with my bike is better quality anyway. The stock chain ring didn't properly align with my rear sprocket for the pedal chain. The kit 3 piece crank feels like cheap quality anyway.
  8. PocketBiker

    PocketBiker Member


    Looks like you have a nice, clean bike there! Since you opened up a question about the kill switch, I'd like to ask a question about a little different situation. My "kit kill switch" is built into the throttle. I also have an after market horn switch which only would fit on the left handle bar. I would really prefer to have the horn on the right side and the kill switch on the left (just seems a little more natural to me) So, I thought of reversing the wiring, BUT..... I remember there being circuits wired into that kill switch?? Do any of you have any opinion as to whether the two momentary switches could be reversed? I know, I could just wire it up and try but, I'm curious about the circuitry I remember seeing behind that kill switch. Thanks, Jim
  9. bikejock

    bikejock Member

    I would put the horn/light controls on the left. Weird I know but I don't think anyone makes left hand throttle/kill switches. I'm eventualy going to wire up a horn and some lights & turn signals to it so my controll for that stuff would have to be on the left.

    My bike is a red with flames GT Dyno Deuce built in the late 90's & early 2000's incase you were wondering. The last Deuce was made in 2005 I think. Wish they still made them. You can see what it looks like before the motor on my profile page in albums. It's a hard to find bike to. I got lucky and found it on Craigslist for $250. I tried to find the black with flames version but the red was the only one I found that had all the original parts. Seen them with a 2 stroke but don't think anyone ever installed a 4 stroke on that bike (as far as I know)
  10. PocketBiker

    PocketBiker Member

    Oh no, I wasn't suggesting I change the throttle to the left side..... Just send the kill switch wires to the horn and the horn wires to the coil. If I hadn't done such a good job of shrink wrapping the kill switch, connections, I would just try it, but I hate to mess with it now, so I probably will just keep the kill switch on the right side. More than anything, I have wondered .... why all of the electronics, in the kill switch?? (That made me question the idea of switching them)

    I checked out your bike. That's tough looking bike! They are getting harder to find; Really good you could find one! I look forward to seeing it when finished.

  11. bikejock

    bikejock Member

    Thanks. Can't wait to get it running. I'm waiting on a crank axle that allows me to use the original chain ring & bearings because the kit 3 piece axle & chain ring didn't fit well on my bike. Hope to get that part next week. Also getting a fuel filter before its first start up.

    I wish someone would make a little 12 volt stator genorator (like the ones used on motorcycles) so we can run lights & other 12 volt stuff through the 4 stroke motor. I was thinking of a way to rig something up to my motor at some point so I can draw electrical power while the motor is on. has a little genorator that can hook up to these 4 stroke motors but it's limited to a head light at best and they are a bit pricy.
  12. bikejock

    bikejock Member

    Fired up my motor today for the first time. Everything from the throttle to the trannny works fine but the kill switch failed to turn off the motor. Looks like I'll need to re-think my wiring set up. Might need to splice the green wire a different way instead of using the plug.

    What would be the best place to bolt the ground? I don't have a way to test the metal to see if its compatible with the ground wire material. I was able to shut down the motor by unbolting the ground from where I had it.
  13. The_Aleman

    The_Aleman Active Member

    I have my kill switch mounted on the handlebars and the ground for it is bolted directly to the engine. It's always worked for me.

    Attached Files:

  14. bikejock

    bikejock Member

    I guess it was because of where I bolted my ground. I'll move it to where you have yours & give it another try.

    Also whats a good way to connect the green positive wires together? I don't think the plug I had it hoked up to was connecting them together very well. I think that's why my kill switch failed to operate correctly.

    Hope my kill switch isn't defective.
  15. KCvale

    KCvale Motorized Bicycle Vendor

    The 142F's with the long wire and connector are the easiest, it's the ones with the red kill switch that get harder.

    Just run your handlebar kill button wire down with the throttle cable to the gas tank, and the engines kill wire up with the throttle cable or gas line to the gas tank and connect the pair there.


    Color don't matter.
    Just whack both pair off where you want them to meet with ~1.5" overlap.
    Then slide 2.5" piece of shrink wrap on one of the wire pairs first, then stagger cut the 2 pairs.

    A 'stagger cut' means you leave one wire longer on each pair so when you strip and solder them together the splices are a good 1" apart so you don't need to tape them to isolate them, just slide the shrink wrap over them and heat it up.

    Note: There are no electronics in the throttles kill button.
    It's just a momentary switch and wire color does not matter.
  16. bikejock

    bikejock Member

    I had a leaking fuel valve so I'm waiting on a replacement before I try another start up.

    Also quick question, if my kill switch doesn't work again is it OK to pull the spark plug out to turn the engine off? I wanna know if its OK or not so I don't ruin my engine or something. What I did last time was I just turned off my fuel valve & let the carburetor run out of fuel.
  17. The_Aleman

    The_Aleman Active Member

    All you need to do to shut the engine off is to ground the coil wire. I don't recommend pulling the spark plug boot to do so.
  18. KCvale

    KCvale Motorized Bicycle Vendor

    Had to do it several times.
    Depending on what you are wearing and standing in (barefoot in water) it can be shocking experience, but it won't hurt your engine any.
  19. butterbean

    butterbean Well-Known Member

    It doesn't really matter about the circuits wired into the kill switch, the horn and kit kill switch are two different types of switches. The kit kill switch is normally closed, meaning until you press the button, the circuit is closed, and pushing the button interrupts the circuit. The horn button is normally open, meaning until you press it the circuit is open, and pushing it closes the circuit. So hooking the kill switch wires to the horn would actually mean the bike wouldn't run without the button being pushed.
  20. KCvale

    KCvale Motorized Bicycle Vendor

    I don't know what kind of kit you are using, but throttle kill buttons are normally open and close when pushed to simply ground the coil wire to kill the engine.

    It won't hurt to use the throttle button for your horn and a different NO button for the kill.
    Just make sure it's easy to get to get to so you can kill your engine in the event of a problem like a stuck throttle or you fall over and get pinned.

    If your gas petcock is not bad you can stop a leak by wrapping the threads with Teflon tape and screwing it back in.