That's very interesting.  BTW, what's the status on your custom fuel tank?

Update on the seat mod.

Top view...notice the slot cut in the metal at the front of the pan...this is for the metal seat bracket that bolts at the gas tank to slide into and hold the front of the seat pan in place.  I will be making brackets for each side of the seat pan  to bolt to the stock seat brackets on the frame.


Bottom view with black rubber bumper pads where it sits on the frame, front & back.  

Side view with trimmed down foam...a full sheet of gel will go on top of this from end to end.  This foam is about 1" thick and the gel will be 1.25".


These next 2 pics show slightly different points of view of the side to show the shape of the pan.




At this point the seat pan is shaped the way I want it.  It sits on the frame front and back on the hard rubber bumper pads (from another donor seat of some kind).  The front of the pan goes up onto the bottom of the tank a little, with the foam/gel going up a little farther.  Once the cover is back on I am hoping the seat cushion will "hug" the bottom of the tank and provide a frontal cushion that will prevent the "sliding forward" that is so pronounced on the stock seat.  I also will have the foam/gel cushion extend down from the front area of the seat to provide support and comfort for the inner/upper thigh area....like some of the sport bike seats.  The shape of the bottom of the pan give the seat a much flatter sitting position and also provides more room to move back a little, with better support behind.

I just remembered one point.  The sides of the pan near the front, just before the pan bends up...I think I will be reforming that area a little so that it folds down and will thus give more comfort to the inner thigh area.

That is the plan anyway, we shall see how it works out.

The seat cover from the donor Corbin seat, though the design is a bit dated, is a fine cover and I want to reuse it once the base and cushion shaping is complete.  There is a small boat seat cushioin business in the local area and I will be talking to them about some slight modifications to the cover for a more perfect fit.  My wife and I can both sew but I want this to look really good.