I was able to get a chunk of work done on the seat. First a pic of the seat post:
This fine piece of work came from Chop Shop Customs. Since the only 5/8" post clamps I could find were in the $20-30 range, I figured I would go with another idea and using the front mount as a pivot to work with the suspended sissy bars. I made a mistake in not allowing a bit of clearance between the seat's mounts, so a little grinding was in order. After grinding, I prepared to fill the hole by covering one side with the same aluminum duct tape I used for the brake bracket. The Nail clippers are there to keep the end level.
I was afraid I would have problems drillin' the fillin'; and I need a 3/8" hole for mounting. So to form the mounting hole, an Uno card gave the ultimate sacrifice. I wrapped the card around a 11/32 drill bit, and used my favorite tape to hold its shape; lething the tape overhang the edge of the card to give it a sticky foot to attach to the tape on the bottom side.
The hole is purposely off center to save from having to grind much more of the seat post. While trying to center it vertically , the tape touched, and that was all she wrote. The medium used to fill this space is 80d polyurethane.
I did a test run, letting the poly set up in the measuring cup, just to get an idea of what I was working with and to insure my measurements worked. Within 10-15 minutes, it was set up, cooling down, and was pretty darn firm. I mixed up another batch, and poured.
I kept an eye on the left over mix. After it had set up, I noticed that the little bit I poured was still tacky. There wasn't enough material there to generate the heat necessary to set up as fast as the left overs. I took the seat post into the bathroom, and borrowed my wife's hair dryer for a couple minutes. Five minutes later, it was no longer tacky.
I took the bottom piece of tape off, trimmed the excess card, and drilled the rest of the card out with a 3/8" bit.
Very little seepage.
I had to drill the seat's mounting tabs out to 3/8". The bolts I am using are stainless 1/4-20 sex bolts, one on each size. I still have to cut down a stainless 1/4-20 bolt, thread lock it into one side, and mount it up for good. I did it this way so that the heads on both sides matched in size.
I have to grind one side just a little bit more, and I will mount the seat post up with a plastic fender washer on each side to avoid metal to metal contact.
Hopefully I get the time tomorrow to finish this up so I can move on to figuring out how to mount the sissy bars.