I have a scooter ignition lock that i got from ebay and i was planning on retrofitting it on a 1980 motorcycle. The thing that i need to make this work is that the ignition lock needs to be closed (let eletricity pass through) when the key is turned and opened (not letting power pass through) when key isn't turned, but it does the opposite. Is there any way to reverse it? (I didn't find any way to do it on the switch and i can't open it)!

link for the switch

The motorcycle has a button that when pressed connects a wire coming from the engine to ground (frame in this case). i would remove the button and connect the wire directly to the ground and put the ignition switch in between so that it acts as a switch and not let the motor start.

(i barely understand english. I live in europe in a small country so i never got a chance to learn english properly and the terminology is correctly said in my launguange but i wrongly translated it)

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    \$\begingroup\$ NOTE - an "open" circuit doesn't let electricity pass through, so make sure you understand the terminology first. \$\endgroup\$ Aug 6 '17 at 13:21
  • \$\begingroup\$ My knowledge of electronics in basic at best but i think that the question is understandable \$\endgroup\$ Aug 6 '17 at 13:41
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    \$\begingroup\$ Why on earth would you not correct an error in your question? It also needs some punctuation repairs. \$\endgroup\$
    – Transistor
    Aug 6 '17 at 13:51
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    \$\begingroup\$ Your comment below Transistor's answer says the switch is working as it supposed to while your question implies that the switch is inverted. Which is it? \$\endgroup\$
    – Oskar Skog
    Aug 6 '17 at 16:02
  • \$\begingroup\$ The switch is working as its supposed to but i need it to be switched and i dont know how to do it i tried using a mosfet as suggested by an friend but didnt understand how to do it \$\endgroup\$ Aug 6 '17 at 16:24

The thing that i need to make this work is that the ignition lock needs to be open (let eletricity pass trough) when the key is turned.

First some terminology:

  • When you close a switch electrical current can flow.
  • When you open a switch the load is switched off.

You must have measured the switch incorrectly. All ignition switches will isolate and turn off the ignition system when in the off position.


simulate this circuit – Schematic created using CircuitLab

Figure 1. Switch logic.


simulate this circuit

Figure 2. The ignition switch will have two "normally-open" (in the off position) contacts. The ignition contact will close when the switch is turned clockwise to the mid-position and the sprung starter contact will close when fully clockwise.

What you need

It seems as if you have bought the wrong switch. If you want to switch off a magneto then you need to short-circuit the points (spark switch) so that it is always connected to ground.

enter image description here

Figure 3. Lawnmower ignition circuit with kill switch. Source: DenGarden.com.

You want a switch that will be closed when the ignition is removed. I'm sorry, but you have bought the wrong switch. The price on the eBay link was US$2.60 so I don't think the error will cost you too much - probably more for postage.

Another possibility

enter image description here

Figure 3. Using a normally open (NO) switch to kill the engine.

If you are able to add the switch you bought at position 1 or 2 it should do what you want.

  • 3
    \$\begingroup\$ Why do you need to reverse it? That's how they're supposed to work. Your question reads as though you are replacing a motorcycle ignition switch and you don't understand how they work. Your comment reads as though you are using an ignition switch for a different purpose and want to change the logic. Please update your question. \$\endgroup\$
    – Transistor
    Aug 6 '17 at 13:59
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    \$\begingroup\$ Clear answer, well done . Let's hope the question gets improved. \$\endgroup\$
    – Solar Mike
    Aug 6 '17 at 14:07
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    \$\begingroup\$ It's probably a small kick-start engine with a magneto ignition system. As such, the way to turn the engine off is to short out the magneto - therefore closed switch == off. \$\endgroup\$
    – brhans
    Aug 6 '17 at 14:38
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    \$\begingroup\$ brhans might be right. OP might be trying to use a regular NO ignition switch when he should have bought an NC type. \$\endgroup\$
    – Transistor
    Aug 6 '17 at 16:07
  • 1
    \$\begingroup\$ See the update. \$\endgroup\$
    – Transistor
    Aug 6 '17 at 17:12

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