I thought the Rotor and Pickup control the spark time. The rotor has magnets attached to it that cause a pulse in the pickup, which the CDI converts to spark timing.
I had a YZF600 stator for a bit. It worked great until the VR burned it up. Now I have a FZR600 stator in a YZF600 case, had to make new mount holes.
The pickup needs to be within specs. It is a very picky item. A bit of either way can cause you to have no spark.
"There he goes. One of God's own prototypes. A high-powered mutant of some kind never even considered for mass production. Too weird to live, and too rare to die." - Fear and Loathing