Simple "keyed ignition"

Discussion in '2-Stroke Engines' started by Bryan Smith, Jun 1, 2009.

  1. Bryan Smith

    Bryan Smith Member

    Hi, I'm building my first bike and learning lots from this site. I ride my bike around to do errands and I often hop off to go in a store for a few minutes.
    I wanted to incorporate a simple keyed switch to slow down anyone who wants to jump on it for a "quick" joy ride. I know they could just throw it in in their truck or pedal away with it, but I wanted to prevent them from "driving" it away under power so for what it's worth, here's my idea.

    The key I'm going to use is a 3/32 phone plug. as seen here:


    I soldered the contacts together on the inside to connect them.

    on the CDI, I cut the blue wire and routed it through a surface mount jack I salvaged from some video equipment. Here is a similar jack that could work:


    When the plug is in, the connection is made and the CDI will work. When the plug is removed and in my pocket, no one is going to be cranking that bike up unless they know the secret.

    I made short wire connections on mine and super glued the components to the CDI. Then, I epoxied over the top of this to make it rock solid and tamper proof. Afterward, I sprayed a little black paint over the epoxy to hide the wire trail. While I was at it, I fitted in a toggle switch beside it to turn off the Engine. Everything is wired in series off the blue wire.



  2. Junster

    Junster Member

    Nice looking job but I'd carry an extra "key" just incase you leave that one on the road behind you someplace from vibration. Cool idea.
  3. pdxrhett

    pdxrhett Member

    That is an awesome idea, although you could use the connector from headphones and solder the wires together outside the little plug in, and have a loop.

    My idea is to hide a switch under the saddle or in some very discreet place and have it wired along the same way as my kill switch so they would never find it :D
  4. EnFlaMEd

    EnFlaMEd Member

    cool idea! I wonder if these is a way to have a solenoid activate a pin that jams up the spokes/brakes/crank etc to stop people from riding your bike away. Something I have always thought about.
  5. Bryan Smith

    Bryan Smith Member

    I got the bike together today and the key works great! WOO! HOO! :cheers2:

    the phone plug has a dimple in the tip and the jack has a spring that catches in the dimple preventing it from falling out without being pulled out on purpose.

    pdxrett had a good idea with the wire loop coming out the end. I'm not sure if it is strong enough to hold the weight of a key ring and a keys though. (Well, maybe a rabbits foot chain would be appropriate) but That might be pushing it. One positive thing...if the key fell out you'd know where to look for it on the road as the bike would quit.

    As for the solenoid auto lock...That's thinking outside the box! I wonder if it might require too much power to keep the solenoid open and I'd sure hate to think what would happen should the engine die while you are going at full speed. :dead:
  6. pdxrhett

    pdxrhett Member

    Maybe have a bike's disc brake caliper hold the front crank in place? The caliper would only activate once the bike is completely off? Would only work in a shift kit though :p