I have a 96 Indy rmk 600 with 2004 700 engine. The snowmachine sat in pawn yard for about a year it ran fine prior to that. When I got it back I took it apart and noticed one piston had started to concave on top so I replaced them both put the engine back in and now no spark. Also can't find the main ground wire. How do I test to check for good CDI?