Only running on one cylinder

[hazard2k]

2004 Polaris classic 550 fan cooled
Started it up this season and found that only one of the cylinders is firing. I tried new plugs and same thing. I hook a spark tester up to the coil pack and notice only one of the wires is producing spark.

Is there a way to test the coil pack to see if it is bad, or should I start looking into the CDI box or possibly even the magneto?
Thanks, Jeff

[yamahamtc]

just replace the ignition coil it should do the trick. check all your connectors to the coil as well