I need some help as to where to check first before a lot of cash is spent. Bike was running fine, then just died. Got it home, looked about and found the light wire had touched the frame and grounded it out. Moved wire, and it started. Was end of season, so replaced the clutch, put her back together and nothing. I seem to have no spark anymore. Which is most likely, coil or magneto? How can I test? Thanks