My first step was to create a new false tank. I was lucky enough to find someone selling one on eBay that was just an hour away. Since this bike is my daily driver I took it to go get replacement parts. To say the trip back was ungainly was a bit of an understatement
I have been told that GL1200s are hard to strip down but this was a perfect excuse to play with fiberglass. I started by cutting away the sections of the false tank that mold to the front fairing.
I then glued and wedged foam insulation sheeting material together to make a structure that is larger than the potential area that was needed.
I am lucky to have access to an Aerospace Engineering lab at my university. Frequently as a Senior Design project, they create foam structures then use fiberglass and carbon fiber to create flight surfaces which are then placed in wind tunnels. I was able to check out a hot wire cutter which cuts through the foam, not unlike butter.
This was the final shape that I settled on. Now if I were to do this again by hand I would make the curve larger as it looks a bit small to my eye on the bike. Another option I have is to learn how to 3d model and create the entire shape from scratch. I may end up doing this.
Then, I draped it with aerospace-grade fiberglass sheeting and epoxy. I had to do 4 layers on each side and had many small patches. Adding plastic sheeting between the fiberglass and the foam would have been smart as chiseling the foam back out was not fun. I am very happy with the symmetry of the shape given that I was just eyeballing it.
From there I sanded the shape with 80, 200, and 400 grit sandpaper to make a smooth surface.
Then I used a sandable spray paint primer and Rustoleum rattle can paint for the first paint job. I may redo this in the future.
While I was lucky to get all of the supplies for this (except for the paint) for free this is an easy but time-consuming process. I would guess you could do this for under $50
