Complete loss of power

Hey guys, the other day I took a short trip to the grocery store and when I went to leave I lost power. 

It happened when I moved the starter switch from off to on and when I pushed it to crank the starter motor the whole bike went dead. No headlight, no instrument lights, and no starter--completely dead. I tried a few times and eventually it came back to life and started. 

I figure I need a new starter/kill switch but before I buy am I correct to assume this was caused by the starter switch? I can see the starter switch causing a no-crank issue but can it cause the entire bike to go dead? 

 

I'm thinking you may have a bad connection somewhere along your main power wire as it affects everything.
It could be as simple as a dodgy fuse connection.

If you can replicate it,
get your meter on DC V.
 
In failure mode, bike key switch on.
Black probe on negative battery post(metal part of battery)
Red probe on positive battery post.
Note voltage

Move the red probe only, probe the fuses, both sides.
You should have battery voltage within a few tenths on both sides of all fuses. Anymore than a few tenths difference may be a bad connection.

Move the red probe to the engine case.
This will test your ground connection
Voltage should be less than  0.5V
If it's 0.5V or more you have a bad ground connection.

Battery can also be an issue, but do these tests first.

Oh, everything must remain connected.  Do not disconnect anything otherwise the tests aren't valid.

Okay feeling pretty stupid now...went to check the voltage at the fuses as you described and discovered the negative battery cable was loose. Owning a 40yo motorcycle is driving me crazy. I always assume something bigger is wrong. 

That's all it takes
Good job!