Wiring a stock motor - Disregard your manual

Discussion in 'Electrical' started by DuctTapedGoat, Dec 11, 2010.

  1. DuctTapedGoat

    DuctTapedGoat Active Member

    This is proper wiring of a stock motor. The instruction manual, well, it lies to you. Disregard what your manual says about the wiring pattern. The purpose of this guide is to help other people who have dealt with the same problem I did when I was on my first build, which was that my kill switch did not work. It seemed to TRY to work, but it just reduced the power of the engine. This is the fix for that issue. I will explain why at the bottom of the post.

    :D :::::WIRING GUIDE ::::: :D

    Okay, first we will take note of our wires.

    NOTE: Different brands tend to use different colors for some wires, so use the process of elimination to determine what color a wire is if it is not stated here.

    *Kill Switch Wires : Black Wire & Red/Yellow Wire.
    *Engine Wires : Green/Blue Wire & Black Wire & White Wire.
    *CDI Wires: Green/Blue Wire & Black Wire.
    *Other Stuff: Wire Cap & Ground (Two most common spots are the water bottle screw after removing all contact paint, the bracket below the CDI and grounding to a CDI screw after sanding paint off the frame where bracket comes in contact with the frame.)

    Now that you know what wires you have, it's time to connect them.

    1. Engine's Green/Blue Wire to CDI's Green/Blue Wire.
    2. Engine's Black Wire to CDI's Black Wire.
    3. Kill Switch's Black Wire to Engine's & CDI's Green/Blue Wire.
    4. Kill Switch's Red/Yellow Wire to Ground.
    5. Engine's White Wire to Wire Cap.

    Go ahead and fire up your bike real quick so you can test your brand new fully functional kill switch!

    I don't know why the instruction manuals tell you to connect the white wire from the engine into the circuit. That's the ~7V live wire intended to be used by extra bike devices, like lights and such and such. When that white wire is in the circuit, the kill switch will not be able to stop the motor.
    Ollie likes this.

  2. GearNut

    GearNut Active Member

    Some manuals tell you to use the white wire as a kill wire only because it does work most of the time. Most of the time as you have found out. Doing so effectively shorts out the lighting coil of the mag, overwhelming it and reducing the signal that it sends to the CDI box.

    FWIW, this subject has been discussed to death, resurrected, and beaten to death many, many, many times over.

    Do a search on it if'n you get bored some day. :)
  3. Narroc

    Narroc New Member

    Wiring to a Victoria Moped.

    I have a 1959/69s Victoria Moped. Which I recently got and am now trying to restore. I'm puzzled by the wiring to the headlamp assembly.
    At the motor there is a yellow and a red wire Then a red, yellow lead with a small black (all Disconnected at present) which goes up the headlamp, At the head lamp the Yellow is connected to the one side of Switch and then from the same terminal carries on to a long lead which apparently must connect to the headlamp but is not connected? (the yellow does not go though the switch) The red wire again disconnected ends in the headlamp cover. The bulb is a 6v 15/15 watt and appears to be a double filament.
    At the rear of the bike a short small disconnected black lead can be seen hanging out of the tail light assembly.
    What I can't figure out is How the head lamp switch works? Is the dip on all the time and the switch just switches the high beam on/off? so both Hi & Low go on high? Why is the yellow connected to he switch and then carries on to which side of the bulb? What does the black do? is this live feed to and also goes to the tail light?
    Can some one explain this to me?
  4. DuctTapedGoat

    DuctTapedGoat Active Member


    Well, what I'd suggest is really just hook up a multimeter in place of the bulb, connect your wires and go from there.

    There's a chance it's hi/lo but also, you can just replace it with a 3 way switch if you'd like to turn it off completely.

    One thing you could do is look into cars and motorcycles from that era and see if their headlamps were on all time, or if they indeed had a kill switch. Sometimes common sense gets us before we can find the facts - there's a chance they were always on in that era, but I'd be lying if I said for sure.

    Like I said, connect it up and check with a multimeter - that'll be the simplest way to figure it out.
  5. GearNut

    GearNut Active Member

  6. Dave C

    Dave C Member

    My kill switch is connected to both of the CD/motor wires, one lead to each side.

    About that white wire; has anyone tried to use a 6 volt auto-style regulator and small battery?
  7. Ollie

    Ollie Member

    My kill switch had a black and a red/yellow wire. I attached the black to the blue engine/CDI wires and grounded the red/yellow to the frame. It works perfectly now; no more choking it to death and having a hard time starting it up. Thanks for the instructions Mr Goat :)
  8. butterbean

    butterbean Well-Known Member

    Wiring one wire from kill to white and the other from kill to ground has always worked for me. Wiring one wire to cdi and the other to ground will also work. Wiring both kill wires to the cdi will eventually blow it. It does not matter which wire from the killswitch goes to positive and which goes to ground. All the killswitch does is connect positive and negative, shorting the circuit.
  9. HeadSmess

    HeadSmess Well-Known Member

    the cdi only has two wires, and one of them is ground, so how do you wire it to avoid this problem exactly?

    both wires are negative. both wires are positive. its an AC system...

    whats with all the lazarus type threads lately?
  10. Fabian

    Fabian Well-Known Member

    I do agree with the concept of using the white wire (accessory power supply wire) and that is exactly how my kill switch used to be connected. Maybe my magneto's lived a long and happy life because i wasn't creating a dead short circuit in the high tension winding's of the magneto power supply to the CDI.
    Another reason is that i use the choke to kill the engine at all times, except when needing to use the kill switch to stop the engine quickly, reducing the number of events where the magneto experiences an electrical dead short. Thirdly i don't use the kill switch as a jake brake as some people do with the original single speed setup; guaranteeing to overload and burn out the magneto winding's.

    That said, the newer magneto's won't stop the engine when the white wire is plumbed into the kill switch circuit. I don't understand why this should be the case, but for some reason it is. Hopefully someone can explain why?
  11. Donald

    Donald Guest

    I have black white blue from motor. Blue black from cdi. My white wire is doing nothing but sitting out right now. I have blue to blue and black to black. My kill switch goes green to black motor and cdi and yellow red to blue motor and cdi. It was working fine but a little boggy at time's but now today just started loosing power while riding and died. Can't get it to start and no spark. Please let me know what I need to do and how to properly wire this piece please. Lol
  12. HeadSmess

    HeadSmess Well-Known Member

    argh. old thread reanimation. do you eat brains too? :p

    meh. first test. remove killswitch. might be faulty.

    next test, ground the white wire. sometimes they run when thats hooked to earth. strange huh? wire the killswitch to the white wire like the manual says, and one day it dies and only runs when the killswitch is pressed! it makes sense though once you pull one apart and see how the coils are wound/wired internally.

    that doesnt work, get a new magneto...one without the third, white wire... that white wire is a pain in the...behind.
  13. Sasha1234

    Sasha1234 Member

    What if I had mistakenly put the kill switch wires Red to black and Black to blue? Will that fry my whole engine???? Will I not be able to use the motor??? HELP PLEASE!!
  14. butre

    butre Well-Known Member

    no, the cdi is all passive electronics. just switch them back around
  15. jaguar

    jaguar Well-Known Member

    here's two alternative ideas for a kill switch. The problem with the normal setup is that there's a high surge of current that flows through the stator coil when you short it out. That can cause a short circuit and lower the output voltage. The top scheme is the one I used for years with no problems. I'm just guessing at the correct value of resistor to use in the bottom scheme. If it don't work then try a 100 ohm / 10 watt resistor.