As Fred mentioned, the 750 tank mounts just opposite of the 650.
For mine, I first drilled a hole just above/behind the stock cups on the frame (closer to the headlight), with a long bolt/washers, flipped the cups over and bolted them on...worked fine, the 750 tank was solid, but it was a bit higher than I wanted...and the frame's cups were in the way to get the pucks lower...so I drilled out the cup's spot welds and then mounted the pucks a bit lower...to my desired location.
The rear of the tank (where it mounts to the frame) needs to be bent upward to fit into the stock frame mount. I just used a long metal rod to bend it to the desired angle. Go slow here, you don't want to break the tab...a little heat may help...I didn't use any...just took my time and it worked fine.
I didn't take any pics of this process...I don't think. perhaps in my album?
It's pretty easy...good luck.