Using a stator output as a crank wheel

[trailrunner]

Hello, I'm in the planning process of squirting a single cylinder ATV engine. Today I hooked my scope up to the factory crank signal pickup which is a single tooth and the falling edge of the tooth is TDC. I also hooked my scope up to one of the stator output wires and found that it makes some what of a clean 6 tooth square wave pattern per crank revolution. I want to do full spark and fuel control without having to make a custom 36-1 crank wheel. The only thing I noticed that may make it not work is the stator only outputs a full square wave when the system is charging but when it is not charging the duty cycle drops off but the rising edge stays the same. I have attached photos of my waveforms off my scope. Thanks again.

Yellow is Crank signal Blue is stator pulses

[grippo]

As long as the stator rising edge doesn't move and you trigger on that edge you should be OK when it changes duty cycle. The ecu doesn't care about duty cycle. The other thing is to select the single tooth edge that puts it close to the middle point between two consecutive stator pulse rising edges. The only other problem I can foresee is higher frequency noise from the stator pulses that may not show up on your scope.

[trailrunner]

Awesome thanks for the information grippo. The stator rising edge does not change throughout the RPM range. The rising edge of the single tooth currently is a few degrees ahead of TDC but I guess that I can adjust the tooth offset so that the ECU knows were TDC is. I have also attached a closeup of the single tooth with the stator charging and a shot with the engine at higher RPMs.