a few bits of advice re: cb750s:
1) there is no changing plug wires. Stock coils have the wires soldered internally and sealed in so in order to change the plug wire you need to change the coil too. Usually most people run them until the coil burns out and then replace with aftermarket (like dyna or accel). There is a trick where you can snip the old wire (or drill into the coil) and splice in new wire but you will still have that small section of old wire acting as a bottleneck. Unless there is anything physically wrong with the old plug wires, leave them alone and focus instead on the wires going into the coil from the points, because of the heat and location they tend to work loose and sometimes corrode at the contacts.
2) Carb rebuild. Before you plunk down hard earned on a set of carb rebuild kits, know that you will not use any of the hard parts (jets, needles, floats, etc) from any of the aftermarket kits. The stuff is junk and is always out of tolerance (leads to leaky carbs). They are good to buy for the gaskets but that is about it. When you tear down the carbs, take a look at the stock honda stuff, usually you can reuse all the needles and jets after a good hard soak in carb dip. The onyl piece that usually needs replacement is the float needle, if it has a serious ridge worn into the point or the spring in the back of the plunger is shot then you will need a new one. Honda sells those parts individually, so if you just need a needle, you can get one without buying a whole other kit.
3) check the fuse box for corrosion. it is on the left side of that bike next to the starter relay. If the back of the box is corroded then you will just continually blow fuses and not get the bike to start. wiggle the contacts for the fuses and make sure they are not loose - as they corrode they heat up, melt the plastic and become loose. Once they are loose they migrate toward each other and once they touch the bike drops dead.