Nick, removing the tank is only a case of 4 10mm bolts...... and yep, Im sorry to say you have learned the lesson
that old tires and bikes dont mix! For what the Cheng Shins cost (like $50 a pair!) it so not worth having old tires.
The new tires are as grippy as heck and if you dont believe me ask anyone on here... they will tell you the same as me.

Enjoy your tinkering and hope your feeling better soon

M

If you can't fix it with a hammer, you've got an electrical problem.image