I find it hard to tolerate the stock frame tails on these old Hondas. It's impossible to fabricate a cool seat for them because there is no way to make a custom seat pan work on the open frame style they have. And who wants to see the same old crap You can buy online! I like to alter the frame with some bent pipe to create a finished look to the rear of the frame.
First I find a good place to cut the frame tail off...
Then I tack a piece of bent pipe in place inline with the frame..
Once it's where I like it, I weld it in place. Then bend some sheet metal to create a platform to attach the seat pan to. And it really strengthens thing up!
Then I welded in some fabricated pieces to finish up the rough cuts on the rest of the frame. A little primer and paint and it looks like it came from the factory like this!.....
Fiberglass seat pan: This is how I make my seats, be it right or not, I dunno.....First I make a form bigger than the seat itself by stretching duct tape (not the kind made out of ducks!) over the frame. Then I apply the fiberglass while inserting bolts through the form into hole I drilled into the frame....
Then when its dry I cut it down to the desired size 
Then I apply foam to the pan and cut it down to the basic shape I'm looking for
Then I take a sanding disc and shape and smooth the seat to the desired shape. After I'm satisfied I run it over to my Upholstery guy with a drawing of what I want and he hooks me up!..
Thanks to Alan at Conejo Upholstery for always hooking me up!:
