You test the resistance between the two wires coming out of the auto choke. I think they are yellow and green. It should be less than 5 ohms when the engine is cold. I doubt that the auto choke is your problem though. If the auto choke was bad it wouldn't start kicking it either. My zx50 won't start with the starter when it is cold probably 25% of the time. I'm not sure why. The starter will just crank, somewhat weakly, until the battery dies. Then it will fire up on the first kick. I figure that my battery is just weak, or the starter motor is weak. It starts just fine when the engine has been warm though. Usually just a problem on the first start of the day.