i think your talking about the pulser pick up
unhook the wires from the motor ,get a test light -kick it over and see if there is power comeing from the stater/pickup,to the cdi,then check the cdi-coil
there are a lot of cheep test lights at auto stores its always good to have one around
-im not talking about a expensive multy meter just a inexpensive test light,that ground,and hooks up to wires ,and lights up
also go to bike bandit and use the parts finder-- oem- and look at how it is assembled