I was riding my XP for the first time Sunday after rebuilding the carbs, oil lines etc. The ski ran fine but the low voltage light stayed on. After about 2 hours of riding I was slowing down and it shut down. When I got home I realized I didn't have spark. I tested the magneto for resitance and it seems to be within specs. I also tested the kill switch with my volt meter and it seems to be working properly. My question is what and how do I test next. I'm thinking it could be the rectifier or the coil. Are there resistance tests for these? Thanks in advance to anyone who can help.