Checking for spark without key

[Yamadaka]

Am I able to check for spark without a key? If so how?

[dcooke007]

You did not mention what model you have but usually you disconnect the white connector coming from the engine to the main wiring harness. Keep in mind unless you have an engine kill switch turning off the engine will be a little shocking if you start it.

Danny

[Yamadaka]

It's an Ace 90

[Zyx]

Bottom line is, yes you can, but you have to disconnect the ignition switch by unplugging the ground wire. Might be easier to follow with a wiring diagram. If I remember right, the blue wire is ignition, black I'd ground. Others may confirm or correct this.

[rlkarren]

The other way around. Black is ignition, blue is ground. This is true for most, if not all models. At least this is true for the models for which I've studied the wiring diagrams, i.e., 90, 92, (92A), 92B, 92B+, 93, 93A, 93B, 94, 94A, 99. And yes, the first Ace 100's were wired like an Ace 90, identified by the large headlight bucket. With the introduction of the emergency switch in the small headlight bucket, (92B, I believe), the wiring changed slightly.

On an Ace 90, simply disconnect the black wire coming from the magneto to the key switch. Why?.. well, let me tell you... This black wire is spliced into the black wire that supplies the ignition coil inside the magneto. The key switch closes the circuit between the black wire and ground when the key switch is set to off; grounding out the ignition circuit.

You could just disconnect all the wires at the key switch with the same results and eliminate any possibility of a short in the wiring system. The Ace 90 does not need a key switch to run and it's only purpose is a junction to supply power from the magneto to the battery and headlight circuits and to function as a kill switch.

$0.02

Roger

[Zyx]

Now you know why I look at the wiring diagram before working on the bike. Can't remember wiring colors from day to day.