Hi is there any way to check starter switch? My 93 bike is completely dead. Main fuse, starter motor and relay seem ok. All I'm getting is the oil light on

you can check your switch with a multimeter across the points at the handle bars,

however I would suspect one of the other sensors/switches like Clutch Switch, Neutral Sensor, and Kick-Stand Switch. Any of these will not let you start up the bike unless they are in the correct position. Are you getting a neutral light? Is the red bulb for side stand working?

In my experience (1992 CB 400 SF) the easiest way to check the starter switch is working is to see if the headlight turns off when you press it. The starter motor may not run/ engine may not fire depending on a few factors, but the headlight always seems to switch off when I press the button.

Does your bike start with a bump start?