A minimum of 9 volts in the battery is required to excite the CDI.

Also, check the air jets in the carbs. Also check the tank vent....these have a tendency to build up with rust and restrict fuel flow, even when partially blocked (a long, small gauge wire inserted down the vent, a guitar string works best). This vent is located under the gas cap.

Float level can also cause hard cold starting as well.

As for the CR 500 starting technique......there is an easier way to start them.
If you slowly kick the lever on a 500, you will notice what feels like two compression strokes.

This is due to the large bore size, as the piston rises to TDC, and closes the exhaust port, there is a rise in compression. Slowly kick the start lever and you will feel resistance ( as the piston closes the exhaust port).
slowly continue to kick the lever past this point, and you will feel a second compression (as the piston reaches TDC). Return the kick start lever at this point, open the thriottle to 1/4 turn and hold it there..... and give it the boot. It will start first time, even when cold.
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Mike