My son was riding to the fish house, and he said the thing just shut off on him. I had noticed in the last couple of days when I rode it that it would partially cut in and out... like from 50% to 100% part. Very subtle, and only for a half-second. And only at low rpms. Wide open, it went like a bat out of... I have tried to start it, it turns over like normal... hard... good compression. It randomly fires.. a little, but won't actually run. I tried drizzling a bit of gas(mix) into the cylinders... normally this is a sure fire start up. Nope. So, I'm thinking because of the suddenness of the stalling, and the non-response to direct fueling, that this would be an electrical problem. Which part? Coil? CDI? is there a more common failure among those? How can I test them?