Motorcycle fairings, much like other motorcycle plastics, crack quite easily. However, fairings, unlike other plastics, can cost hundreds of dollars to replace. Rather than replacing your cracked fairing, fix it yourself. You can quite easily fix the problem, and make the fix look clean and professional using only basic, common tools.
Plug in your soldering iron to allow it to heat up. Make sure to place it on its stand while it heats up. This will prevent it from melting whatever objects its placed on.
Use an old rag to thoroughly clean the surface of the fairing. Wet the rag if needed, and get the surface as clean as possible.
Use your heated soldering iron to begin melting the plastic just to the edge of the crack together. Don't worry too much about how the fix looks so far, as you will fix that later. Be sure to melt deep into the plastic to allow it to melt together as completely as possible.
Let the plastic cool for several minutes before continuing.
Use fine-grade sandpaper to smooth and clean the fix. Gently remove any ridges and bubbles in the fix, and smooth the surface to match with the rest of the fairing.
If your soldering iron kit includes a flat tip, use this for an easier time spreading the plastic.
Always use caution when using extremely hot tools like soldering irons.