I've seen it done with plywood (1/2" or thicker) and rubber watherstripping. Cut the plywood roughly 1/8" to 1/4" smaller than the seat area. Get some 1/4" to 1/2" weatherstripping and run around the egdes of the plywood where they would contact the seat pan sides. Should be a snug fit. Glue the plywood to the underside of the 'glass pan. Any manner of bolting/clamping this to the frame can be used (I can't recall what the top of the frame looks like on a 750, I've only seen it done on 350's) but the most important factor of course is the need to dampen vibration. The best setup I've seen had carriage bolts (round headed deals) running through the fiberglass and plywood with rubber grommets at the bolt head and in between the plywood and frame.
There are probably better ways, though. I'm kind of a hack.
Honda go sideways!
There are probably better ways, though. I'm kind of a hack.
Honda go sideways!
