I guess start with the basics...replace plugs and wires first, if they haven't been done in a while.
Otherwise a no spark condition would lead to the coil, or you may have one of the safety switches not working properly. You need to check the seat and brake switches. Remember the brake pedal has to be pushed down all the way to start. Parts and manuals are available from the moderator of this site and some others. They are listed in some older posts...
Rattosh51
YT6800