I used a cold chisel and a hammer to remove the nuts. Not the best way to do it and you will need a tool to replace the nut. But at leats with the nut on the bench it makes it much easier to make a tool for replacing them.
I made a simple tool from a large socket, cut to leave two tangs, you could make it with four tangs but why over complicate things. Using an old socket, dosn't matter if it's metric, imperial or whatever as you have to narrow the tangs to fit anyway, allows the use of a torque wrench when tightening
I used a 1 1/8" 12 point master mechanic socket. I used a bench grinder to grind four equally distributed grooves and dressed them square with a good hacksaw blade. Costs $3.70 with tax, Labor 10 min. Works great on my 81 gl1100.