On the plastic parts of the bikes, most of them are injection molded plastic. Some people try to fix them with fiberglass resins and cloth, and that doesn't work well at all, as the resins really do not stick well to the plastic.
Now, to fix most problems with stock plastics, we need to use the right bonding agent with the fiberglass cloth.
Since most plastics are black ABS, simply substitute the resin for ABS cement, and cloth. Works better than anything I have ever used. I just refitted a side cover panel holder to the cover with ABS cement and fiberglass cloth, stronger than the cover itself. I use it inside parts, usually not on the outside, but, a couple of parts needed small holes filled, and I used just the cement, and sanded, body worked the cement, and repainted after it dried a couple of days, you can't tell it was ever damaged.
If you are not familiar with ABS plastics, it is the black drain piping in mobile homes, and houses, glues together with this stuff. Don't confuse it with PVC glue, that is for the white pressure pipes in those locations, and, PVC cement doesn't work on ABS plastics.
