The ignition kill switch can certainly be relocated, from a stricly mechanical point of view. Whether or not this is a good idea is a matter of opinion. All of the switches on the bars, in fact, can be relocated.
There's very little that can be outright removed. Turn signals of course, since you can use hand signals. Headlight and taillight are legal requirements. Starter and solenoid can be removed if you go kick-only. Charging system is necessary, as is the ignition system. Many people relocate these into an electrical box below the carbs, assuming the stock airbox isn't in the way.
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