First thing you want to double check for no spark is to make sure you Kill Switch lanyard is attached or if you have a switch, make sure it's set to the "RUN" position. If that checks out, Then you need to check for spark at the plugs.
One way is to use an in-line spark checker like the one below.
http://www.harborfreight.com/inline-...ker-69014.html
Disconnect the Black/Yellow wire on the coil mounting plate. If spark returns, then you have a short to ground in the wiring of you Kill circuit, or the Kill switch itself may be bad.
If you do confirm that you do not have any spark on any of the plugs, it could be several things. The Stator could be bad, the magnets under the flywheel have broken or come unglued and may be missing, or one of the coil packs, referred to as CDMs may be bad and preventing any of the other CDMs from firing. If the magnets under the flywheel look OK (there are six of them), you can check the stator winding resistance.
Disconnect the Green/White and White/Green stator wires that come out from under the flywheel. Measure the resistance across the wires. It should read 500 - 700 OHMs. If it doesn't read within specs., it's bad. If it reads with specs. go to the next step.
Each CDM has a 4 pin modular connector. Disconnect the connector that is attached to the top CDM. Crank the motor and check for spark on the other three spark plug wires. Do that to all four CDMs until you find one that when disconnected, restores spark to the other three spark plug wires. That's the bad CDM.