Here are some pics of the installation of the speedometer/tachometer on 1 of the minibikes.
^This is the meter. I got it from AliExpress for around $25,-, incl shipping. It's a tachometer (dial) and speedometer (digits) in one. It can be set to km or miles. It needs a 12V powersource. It can also indicate your lighting, blinkers, gearselection (from neutral, to sixth gear) and also an odometer.
^First I did some quick wiring to see if the tachometer would function with this type of engine/ignition.
^The wiring diagram that came with the meter from AliExpress. A lot of function that I will not use, but it was just $25,-.
^This is where I hooked up my remote kill switch wire. I also used this wire for the "speed signal wire". And it works.
^Make sure to have good ground, from battery to engine and to meter. Otherwise it will not function.
^Engine running at idle and the tachometer works fine. So I continued the installation.
^I placed a small 12V 2,9Ah battery, a fuseholder with 5A fuse, a batterycharger connection and a small on/off switch.
^View from the bottom.
^I made some mounts for the meter. The meter came with rubber mounts.
^The speedometer/tachometer came with a sensor and 3 magnets to measure speed. I have milled some blind holes in the front brake rotor for the magnets.
^At first I had installed 3 magnets, as I thought the reading would be more accurate. But in my case I get the best (solid and steady) reading with just 1 magnet installed. That's why I have removed 2 magnets. I also turned the magnet over, because of it's polarity. Now the speedometer works great. The meter can be set with number of magnets and tire circumference to get an accurate reading.
^Batterycharger connected.
^Battery charging.
^The speed sensor installed, with the bracket that came with it.