1992 Ski Doo Safari Electrical Problem

My boyfriend is working on my brother's ski doo 1992 Safari LE 377. He changed broken throttle cables, then no spark, changed CDI box and still no spark. Checked ignition switch, kill switch and toggle but still no spark. Does anyone have any suggestions as to where else to look? We have run out of ideas....
Thanks in advance

1992 Ski Doo Safari Electrical Problem