"First off, I am not a mechani
"First off, I am not a mechanic, more of a broke do-it-yourselfer, so this is not professional advice, just my experience I had with an 86 DT25 with a similar problem. I don’t know if there are safety sensors that might shut down a 99, but if not try this. Check the kill switch 1st. if your not sure if its working, cut the 2 wires leading to it and twist them together. remove the plugs so it doesn’t accidentally start and check for spark at the plug while you turn it over. If no spark, check the stator. Isolate the rectifier wires, they will not impede spark so don’t even bother with them. Find the 2 wires that come from under the flywheel from the stator. On mine, they were black and red. Hook up voltmeter probes, one to each wire, and turn it over. If you get voltage, the stator generator is good and supplying the CDI with power. The hard part is figuring out if the problem is the CDI or the ignition/timing switch. My suggestion is replace the Ign/Timing switch. You may have to take off the flywheel, depending on the location, like I said, my model was older, and I am not familiar with the 99. The Ign/timing switch is much cheaper $ to replace than the CDI. Once replaced, check for spark again. If none, it is probably the CDI. Hope this helps."