nitroxat

My DT400 does not now spark. It had been running, and just stopped. Do you know where I can get a wiring diagram? I think it is a CDI job. I want to try and elliminate each part in turn, starting from the timing sensor in the flywheel. Does anyone have any idea how the sensor works, and how to check it? My fear is that the CDI has died. Can it be tested, or can they be source easily? Thanks