A poor earth will also give you a unreliable voltage reading.
A fuse will pop when the current is greater than the fuse is designed for and as voltages changes so do currents, it could be that everything is now being powered through that fuse as it is the only earth it can find.
This is where we miss GW, there was a year that the wires rubbed through on the frame on the left side between the seat and the foot peg, GW would remember what year that was.
Some of the 19 rides in my shed
2014 V2, Snoopy
2009 Wee, Pumbaa the pig
WR450F, The Blue Postie Bike
YZ250N smoker with rego, Stinky.
Yamaha MT09 (FZ09), The Scud missile.
Club Lead not Club Med.
He with the most toys wins.
Out of my depth in a puddle.
Live life on the edge you will see more that way.
Ridding a motorcycle keeps things in balance.
At the end of each trail and at the end of each day history is made.