White wire is not used (exists for battery charging).
Yellow wire is your normal AC output for lights (has nothing to do with ignition).
The larger single winding on the stator supplies AC to the CDI (it looks different than all the other windings). If it has been soaked or corroded that is likely your problem.
The single winding (exciter coil) should measure 12.7 ohms (+/- 20%) at 20*C.
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2011 EC250E
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