With the rising popularity of custom motorcycles, many home-based bike builders are looking for new ways to shape fairings, which are designed to lend a more aerodynamic form to a motorcycle. If you are thinking about building your own fairings, there are a few key elements to consider.
Basic Fairing Design
Sport bikes require a slippery, aerodynamic form, preferably one capable of creating a streamlined pocket in the flow of air to reduce resistance. Cruisers and touring bikes use fairings as a form of windshield, directing the flow of air over or around the rider to reduce wind-buffeting and exposure to the elements. Take the time to carefully plan out the design of your fairings, sketching your design as you go to flesh it out.
Another factor to consider when designing your fairing is regarding the components present on the bike itself. Sport bike fairings have channels and ducts integrated into the bodywork to enhance cooling and smooth the flow of air as it passes through the bike. This is especially important for air-cooled motorcycles, where the flow of cooling air may be restricted by a fairing. Also, determine how and where the fairing will be mounted.
Fairing Construction Material
Once the design of the fairing is complete, carefully consider the material you will be using to construct your fairing. Most modern fairings are constructed from ABS plastic, fibreglass or carbon-fibre. Fibreglass tends to be the most common media for aftermarket and DIY fairings, mostly due to its lower cost and general ease of use, but it does require a certain amount of preparation.
Start with a basic mock-up of your new fairing before jumping directly into the fabrication process. Sculpt the prototype from clay, cardboard or even spray-foam. There are so many methods available; select one that fits within your budget. Take your time as you develop the mock-up, adding on key elements of your design as you go. Once the prototype mock-up is complete, compare it with your original design sketches and to the bike itself. If it meets your expectations, move on to fabrication. If not, it's back to the drawing board.
The Build Process
Fabrication can be done on two levels: as a one-off piece without a mould or as a moulded piece for mass production. One-offs have the advantage of being less costly, but require attention to detail with the final product. Alternatively, moulded pieces require more work and material on the front end, but leave a polished finished product. Begin by layering a skin of fibreglass (or other suitable media) over the mock-up, building up layers as needed for your intended design. This skin will require smoothing with body filler and a grinder, leaving it ready for paint and fitment if being used as a one-off. For moulded pieces, this skin will form the plug, which a mould will be built around.