INFORMATION:

A four stroke engine only requires a spark in the power stroke. Most ignition systems introduce a wasted spark to simplify the setup. This means the ignition will spark both at the power stroke and the intake stroke. Since there is no fuel present at the intake stroke, there will be no combustion. This is general practice in most OEM ignition systems. Even more, a crankshaft mounted ignition will always generate a wasted spark, since it can not obtain any information about the stroke the piston is in.

If you don't want a wasted spark, f.e. for energy saving reasons, you can choose a system that does not create a wasted spark. To select the correct system, it is important to know the top dead centre interval. See the image(s) on the left to determine which system suits your engine.

If your bike is equiped with a charging system or you are not sure about the firing interval, we recommend to choose the wasted spark type.