You’ll need specialized equipment to check the power pack but the ignition coils and charge coil and sensor under the flywheel can be checked with an ohmmeter. I don’t have the specs handy for them but someone here should.
One possible problem area to check would be the Amphenol connectors. The wires going in can be broken off inside the connector or the pins can be pushed out when reconnecting them. Corrosion in the connectors will cause issues to. If the pins are damaged, a new one can be crimped and soldered on quite easily. Also, check the wiring to the kill switch for shorts to ground. Any of these issues can cause a no start issue.
