My GT500 came with an original Suzuki side cover that was in unfortunate condition. Bits had broken off and been fixed with electrical tape. The slots that hook the side cover onto the bike frame had broken away and had been replaced with coat hanger wire, epoxied in place. The numpty who did the repair used the inside of the side cover as his epoxy mixing tray. The inner guide tube for the retaining screw was broken and the side cover was cracked in several places.
While NOS and reproduction side covers are available from assorted online sellers, I decided to try my hand at fixing up the ratty old one. This might be a handy skill to develop and I need an extra side cover to practice my nascent painting skills.
ABS plastic that Suzuki side covers are made from will chemically bond with Polyester resin. In fact styrene, which is the organic solvent that gives polyester resin its characteristic odor, will soften and left long enough, dissolve ABS plastic. So, a repair attempt using fiberglass seemed like a good strategy. Multi layers of fiberglass would be applied to the inside of the old side cover for strength and a single thin layer applied to the outside for the finish. Gelcoat applied on top of the outside and sanded smooth would act as the primer. The old side cover itself would end up serving as a form but not provide any mechanical strength.
I?m hoping that this fiberglass sandwich construction will provide a better paint base than the stock ABS plastic.
In the photo is a NOS ABS plastic side cover done up by Dave Litke. He had warned that with the flexibility of the thin ABS, it would be a challenge to get a good factory grade finish and a custom polished finish was out of the question. You can see slight oil canning effect in the middle of the side cover and slight crazing on the surface. This degradation is less likely to occur on a fiberglass surface.
Another reason for fiberglass is that I happened to have a supply of polyester resin and fiberglass cloth leftover from a long-ago boat repair job. My old supplies also included a bit of fiberglass gelcoat. My first step was to buy some fresh fiberglass catalyst and mix up test samples of resin and gelcoat to ensure that the polyester and gelcoat still worked (i.e. it still hardens).
I then carefully pried and ground off the epoxy, old paint and detritus from the inside of the side cover. The main tool for this was my trusty Dremel, set a low speed, using an oval shaped burr. The side cover is not the smallest area to clean up with such a small grinding bit but in the end it only took about 30 minutes. After this I added a layer of lightweight 6 oz cloth, 2oz matt, and another layer of 6oz cloth.
With a bit of strength from the inside layup I turned the cover over and sanded off the old black paint. A bit of glazing putty was used to fill the cracks.
The outside thin layer was done with the very tightly woven lightweight fiberglass cloth. This specialized lightweight cloth is sold in hobby shops for model airplane construction. After that I glopped on gelcoat with a disposable paintbrush. The purpose of the Gel Coat was to act as a filler?,most of it (including brush strokes would all be sanded off)
Next step sanding followed by another layer of gelcoat--this one sprayed on.
After that a 'guide coat' (whatever black spray can is handy) and another sanding to remove all the low spots shown up by the guide coat. Next step will be metal flake man!.
