If you unscrew the spark plug cap from the coil wire & hold it about 3/8ths of an inch from a valve cover bolt the spark will be audible as well as easier to see.
If you can only get a spark by getting within 1/4 inch or less air gap between wire & valve cover bolt to get a spark, one or more components may be at fault.
If you still can't SEE a spark, hold your finger on the tip of the wire and Feel for any current while cranking.
It's just a few (tens of) thousand volts, not much current. Not likely to kill but like PDWest said, you'll know right away if the problem is the plug or the rest of the ignition system.
But, if you have a pacemaker, I would not do it that way.
Stick a screwdriver up in the boot, hold it by the insulated handle and very close but not touching something on the bike that is grounded. Hit the starter and watch for the spark. The engine is painted, it might not work so you'll have to get close to an unpainted screw or bolt.
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