GRATCH
HUGE MEMBER
+1 to that, but usually, from memory, on the Honda's I've had, those switches inhibit cranking.
Run/stop switch on my old '91 cbr6 lets it crank over but not fire.
If you had an engine firing on 3 cylinders would you take off the cylinder head and replace valves and pistons first or would you check plugs, leads, coils etc first.