I have a 2000 Honda VT1100 Shadow Spirit. I am not sure the 750's or later models have the same setup, but it is a place to start.
"REMOVAL"
Remove the rear seat bolt. (It is located at the rear of the back seat at it's base; centered, and more or less straight down from the backrest.
Remove the rear seat by pulling it up, back, and then up and forward.
Remove the front seat bolts. (there are two, centered at the back base of the now exposed front seat).
Remove the front seat by pulling up and back.
unbolt it
Remove the bolts holding the seat on each side and then slide the seat back.
Loosen and remove the two Allen bolts at the rear end of the seat. Then, pull the seat back and upward.
Remove the two Allen bolts at the rear of the seat with a hex wrench, then slide the seat backwards.
Remove the two Allen bolts at the rear end of the seat with a hex wrench, then slide it back.
Remove the two Allen bolts at the rear end of the seat with a hex wrench, then slide it back.
Remove the two Allen bolts at the rear end of the seat with a hex wrench, then slide it back.
Remove the two Allen bolts at the rear end of the seat with a hex wrench, then slide it back.
Remove the two Allen bolts at the rear end of the seat with a hex wrench, then slide it back.
Remove the seat. You will find the battery under it. Remove the negative terminal first, then the positive terminal.
Under the seat. Remove the the bolts holding the seats and you get to the battery.
Remove the seat. The battery is under a cover right under the seat and next to the gas tank. Remove negave terminal first, then positive terminal. Release strap holding battery. Pull out battery.