First off, hey y'all, and thanks for having me. I've had for several years now a CDI-equipped XT 500 that was once a flat-tracker at Daytona, and is now my personal horse. Since I've had it, I've swapped the OEM coil for a Ford truck coil with Chrysler external resistor(when my original one went out, I didn't wanna get raped by the Yamaha shop in town for a replacement), and have had many, many long hours of good riding on it. The bike sat for a year and a half while I went overseas in OIF 1, and when I came home, I changed the oil, gassed it up, and was riding on the 3rd kick. All in all, this has been such a dependable and STRONG bike that, despite its hideously repulsive appearance(my fault), I can't bring myself to get rid of it! And here we are at today. I just finished plumbing a new 1 3/4" exhaust into a car catalytic converter mounted in the stock location(had a headerpipe swung down under the peg and into a megaphone straightpipe... LOUD) to make it more woods-friendly, checked the spark, and found none. I've checked out the magneto/stator thingy in the flywheel, all wires, the coil resistor, and even bought a new coil to make sure that wasn't the issue. Still no spark, not so much as a jolt to the finger when I held the plug wire. All I can assume is that the CDI box is bad, so before I drop money on another'n, I'd like to know if there's anything I may have missed. Also, if I do need a new CDI, is there any other bikes that used the same box? I'd rather not have to get raped by the Yamaha shop(would you believe they want $5 for the same spark plug I got at Carquest for $1.89???), so I'll be hitting up a couple of bike boneyards in the area. If it helps, I do know it's a NipponDenso box, and I have the part number at work if needed. Thanks for y'all's help, I'm hurting for a good ride!