I just purhased a bone stock 1998 WR400. I have studied all of the "free mods" and I have studied the wiring diagrams for the bike. The wiring diagram has a gray wire and a black wire w/gray stripe coming from the CDI unit to a two wire connector. From the connector on there is only the black wire w/gray stripe that runs to the engine cut-off swith and then to ground. As I have not taken anything apart yet, here are the questions: 1. Is this the gray wire described in all the "free mod" descriptions? 2. Unless there is a jumper and the gray wire loops to the black w/gray stripe wire, providing some type of feedback to the CDI unit. Why does this effect the CDI spark mapping? It's not that I don't believe everyone that says there is a significant performance improvement, it's just that it's too cold to ride here in Michigan and inquiring minds need to know!