The OEM plug wires are molded into the coils, so they can't be changed. A few 3-ohm coils out there will let you install your own wires, but those coils will drain all the power these bikes can muster, so they are a bad choice for them. The 750 can just barely hold the battery charge up of driven mosotly on the hiway with those coils, but other than that, don't use those on these bikes, it won't go well.
I've seen a [silly] 'wire splicer' from some Japanese maker that lets you try to splice in new wires: these don't work well in humid climes, though. In desert areas they will work for a while.
Honda still sells the coils as a full unit, brackets and all, about $150 for the set. You can get some drop-in replacements by Sakura (PartsNmore #17-6823) If you don't mind mis-matching the wire colors, or else swapping the bullet connectors so they fit in correctly. The Dyna 5-ohm coils work well, if expensive, and seem to last a long time. Just use some resistor plug caps with any of these for best results.