I have a 1997 formula z 670 which ran excellent last year 4000 miles on it. Anyhow brought it to reputable shop to get serviced oil change ,carbs cleaned , new carbides and a few other odds and ends which i trust were done right. Anyhow i drove 8 miles or so trail riding then returned on a straight a way hammering when the sled seemed to run out of gas . Plenty of good gas in tank. Plugs were dry. Checked for spark and seemed to have spark on one wire not the other . Changed plugs to new ones and had some but seemed weak spark. A small splash of gas to engine and pulled wanted to start but seemed as if it was starving for gas. Checked plugs again and had some gas on them changed plugs again. Now have no spark. I have been researching and found only this possible coil, module, cdi box, or stator. Would anyone have the time to give a bit of advice? Truely appreciate it. I love this sled!