To check the spark, you must :-
Remove the spark plug.
Reattach the plug lead to the plug.
Hold the plug (threaded part) firmly to an earthed part of the bike, e.g. the metal near the plug hole. (taking care to hold only the insulation, as it's a HIGH voltage)
Switch on, and get someone to press the starter, while you watch the gap at the tip of the plug, for a spark.
